Revert of Improve usage of window rectangles (patchset #9 id:160001 of https://codereview.chromium.org/2289363005/ )

Reason for revert:
broke build. See

https://build.chromium.org/p/client.skia/builders/Perf-Win8-MSVC-ShuttleA-GPU-GTX960-x86_64-Debug/builds/186

Original issue's description:
> Improve usage of window rectangles
>
> * Skips non-AA diff rect elements and replaces them with window
>   rectangles.
> * Places window rectangles in the interiors of antialiased diff rects.
> * Arranges two overlapping window rectangles in a plus shape inside of
>   diff rounded rects.
> * Enables window rectangles when clearing and generating clip masks.
>
> GTX 960 perf result (with vs. without window rectangles):
>
>                               glinst4                msaa16                 gpu
> keymobi_pinterest.skp         0.48 -> 0.17 [ 35%]    2.77 -> 1.49 [ 54%]    0.22 -> 0.16 [ 70%]
> keymobi_digg_com.skp          0.42 -> 0.23 [ 55%]    2.34 -> 1.08 [ 46%]    0.25 -> 0.21 [ 83%]
> desk_jsfiddlebigcar.skp       0.28 -> 0.16 [ 59%]    1.70 -> 0.96 [ 57%]    0.19 -> 0.14 [ 70%]
> top25desk_wordpress.skp       0.45 -> 0.18 [ 40%]    2.78 -> 1.53 [ 55%]    0.21 -> 0.19 [ 94%]
> top25desk_weather_com.skp     2.01 -> 1.93 [ 96%]    23.5 -> 2.54 [ 11%]    1.90 -> 1.68 [ 88%]
> keymobi_blogger.skp           0.57 -> 0.37 [ 65%]    2.87 -> 1.54 [ 54%]    0.43 -> 0.33 [ 77%]
> keymobi_linkedin.skp          0.32 -> 0.17 [ 51%]    1.93 -> 1.04 [ 54%]    0.17 -> 0.15 [ 91%]
> keymobi_bing_com_search_...   0.29 -> 0.25 [ 83%]    1.85 -> 1.23 [ 66%]    0.50 -> 0.24 [ 48%]
> keymobi_theverge_com_201...   1.00 -> 0.67 [ 68%]    9.46 -> 3.84 [ 41%]    0.72 -> 0.65 [ 90%]
> keymobi_sfgate_com_.skp       1.56 -> 1.13 [ 72%]    4.49 -> 2.86 [ 64%]    1.54 -> 1.11 [ 72%]
> keymobi_ftw_usatoday_com...   0.59 -> 0.34 [ 57%]    2.80 -> 1.54 [ 55%]    1.21 -> 1.20 [ 99%]
> keymobi_shop_mobileweb_e...   0.46 -> 0.32 [ 70%]    2.60 -> 1.26 [ 48%]    0.35 -> 0.34 [ 97%]
> keymobi_cnn_com.skp           0.68 -> 0.42 [ 63%]    3.40 -> 2.10 [ 62%]    0.49 -> 0.45 [ 93%]
> keymobi_plus_google_com_...   0.77 -> 0.46 [ 60%]    4.83 -> 3.56 [ 74%]    0.52 -> 0.46 [ 89%]
> keymobi_wordpress.skp         0.50 -> 0.40 [ 81%]    2.60 -> 1.31 [ 50%]    0.40 -> 0.37 [ 91%]
> keymobi_androidpolice_co...   0.84 -> 0.73 [ 87%]    4.15 -> 2.05 [ 49%]    0.77 -> 0.67 [ 87%]
> keymobi_online_wsj_com_h...   0.55 -> 0.43 [ 78%]    2.91 -> 1.66 [ 57%]    0.45 -> 0.41 [ 90%]
> keymobi_iphone_capitolvo...   1.18 -> 0.96 [ 81%]    6.26 -> 4.96 [ 79%]    0.95 -> 0.92 [ 97%]
> keymobi_wikipedia__1_tab...   0.46 -> 0.41 [ 89%]    2.51 -> 1.24 [ 49%]    0.40 -> 0.38 [ 95%]
> keymobi_wikipedia__1_tab...   0.46 -> 0.42 [ 90%]    2.52 -> 1.25 [ 50%]    0.40 -> 0.38 [ 96%]
> keymobi_boingboing_net.skp    0.62 -> 0.56 [ 90%]    3.15 -> 1.80 [ 57%]    0.61 -> 0.56 [ 92%]
> keymobi_cnn_com_2012_10_...   0.86 -> 0.82 [ 95%]    2.81 -> 1.50 [ 53%]    0.91 -> 0.83 [ 91%]
> top25desk_techcrunch_com...   0.61 -> 0.56 [ 92%]    3.03 -> 1.76 [ 58%]    0.62 -> 0.56 [ 91%]
> top25desk_ebay_com.skp        1.18 -> 1.08 [ 92%]    2.23 -> 1.24 [ 56%]    1.14 -> 1.09 [ 96%]
> desk_css3gradients.skp        0.64 -> 0.61 [ 95%]    2.99 -> 1.54 [ 52%]    0.62 -> 0.61 [ 99%]
> top25desk_blogger.skp         0.61 -> 0.59 [ 96%]    2.50 -> 1.37 [ 55%]    0.60 -> 0.57 [ 95%]
> keymobi_nytimes_com_.skp      0.65 -> 0.64 [ 98%]    2.69 -> 1.42 [ 53%]    0.62 -> 0.59 [ 96%]
> keymobi_wowwiki_com_worl...   0.99 -> 0.92 [ 92%]    3.46 -> 2.06 [ 60%]    0.98 -> 0.95 [ 96%]
> keymobi_cuteoverload_com...   1.37 -> 1.26 [ 92%]    3.24 -> 2.45 [ 76%]    1.38 -> 1.35 [ 98%]
> keymobi_mobile_news_sand...   0.88 -> 0.81 [ 93%]    3.50 -> 2.07 [ 59%]    0.82 -> 0.81 [100%]
> top25desk_linkedin.skp        0.87 -> 0.87 [100%]    2.92 -> 1.73 [ 59%]    0.94 -> 0.86 [ 91%]
> top25desk_docs___1_open_...   1.43 -> 1.36 [ 95%]    1.87 -> 1.42 [ 76%]    0.73 -> 0.66 [ 91%]
> keymobi_reddit_com_r_pro...   0.68 -> 0.66 [ 96%]    2.49 -> 1.23 [ 49%]    0.65 -> 0.66 [102%]
> ...
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2289363005
>
> Committed: https://skia.googlesource.com/skia/+/db42be9a326c747ff92ed1da8c3536c5b3e8e22b

TBR=bsalomon@google.com,egdaniel@google.com,robertphillips@google.com,csmartdalton@google.com
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=skia:

Review-Url: https://codereview.chromium.org/2312173002

25 files changed, 192 insertions, 690 deletions

diff --git a/gm/windowrectangles.cpp b/gm/windowrectangles.cpp
deleted file mode 100644
index 96c4ea6e48..0000000000
--- a/gm/windowrectangles.cpp
+++ /dev/null
@@ -1,305 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "gm.h"
-#include "SkClipStack.h"
-#include "SkRRect.h"
-
-#if SK_SUPPORT_GPU
-#  include "GrAppliedClip.h"
-#  include "GrDrawContext.h"
-#  include "GrDrawContextPriv.h"
-#  include "GrFixedClip.h"
-#  include "GrReducedClip.h"
-#  include "GrRenderTargetPriv.h"
-#  include "GrResourceProvider.h"
-#  include "effects/GrTextureDomain.h"
-#endif
-
-constexpr static SkIRect kDeviceRect = {0, 0, 600, 600};
-constexpr static SkIRect kLayerRect = {25, 25, 575, 575};
-constexpr static SkIRect kCoverRect = {50, 50, 550, 550};
-
-namespace skiagm {
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-class WindowRectanglesBaseGM : public GM {
-protected:
-    virtual void onCoverClipStack(const SkClipStack&, SkCanvas*) = 0;
-
-private:
-    SkISize onISize() override { return SkISize::Make(kDeviceRect.width(), kDeviceRect.height()); }
-    void onDraw(SkCanvas*) final;
-};
-
-void WindowRectanglesBaseGM::onDraw(SkCanvas* canvas) {
-    sk_tool_utils::draw_checkerboard(canvas, 0xffffffff, 0xffc6c3c6, 25);
-    canvas->saveLayer(SkRect::Make(kLayerRect), nullptr);
-
-    SkClipStack stack;
-    stack.clipDevRect(SkRect::MakeXYWH(370.75, 80.25, 149, 100), SkRegion::kDifference_Op, false);
-    stack.clipDevRect(SkRect::MakeXYWH(80.25, 420.75, 150, 100), SkRegion::kDifference_Op, true);
-    stack.clipDevRRect(SkRRect::MakeRectXY(SkRect::MakeXYWH(200, 200, 200, 200), 60, 45),
-                       SkRegion::kDifference_Op, true);
-
-    SkRRect nine;
-    nine.setNinePatch(SkRect::MakeXYWH(550 - 30.25 - 100, 370.75, 100, 150), 12, 35, 23, 20);
-    stack.clipDevRRect(nine, SkRegion::kDifference_Op, true);
-
-    SkRRect complx;
-    SkVector complxRadii[4] = {{6, 4}, {8, 12}, {16, 24}, {48, 32}};
-    complx.setRectRadii(SkRect::MakeXYWH(80.25, 80.75, 100, 149), complxRadii);
-    stack.clipDevRRect(complx, SkRegion::kDifference_Op, false);
-
-    this->onCoverClipStack(stack, canvas);
-
-    canvas->restore();
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-/**
- * Draws a clip that will exercise window rectangles if they are supported.
- */
-class WindowRectanglesGM : public WindowRectanglesBaseGM {
-private:
-    SkString onShortName() final { return SkString("windowrectangles"); }
-    void onCoverClipStack(const SkClipStack&, SkCanvas*) final;
-};
-
-/**
- * This is a simple helper class for resetting a canvas's clip to our test’s SkClipStack.
- */
-class ReplayClipStackVisitor final : public SkCanvasClipVisitor {
-public:
-    typedef SkRegion::Op Op;
-    ReplayClipStackVisitor(SkCanvas* canvas) : fCanvas(canvas) {}
-    void clipRect(const SkRect& r, Op op, bool aa) override { fCanvas->clipRect(r, op, aa); }
-    void clipRRect(const SkRRect& rr, Op op, bool aa) override { fCanvas->clipRRect(rr, op, aa); }
-    void clipPath(const SkPath&, Op, bool) override { SkFAIL("Not implemented"); }
-private:
-    SkCanvas* const fCanvas;
-};
-
-void WindowRectanglesGM::onCoverClipStack(const SkClipStack& stack, SkCanvas* canvas) {
-    SkPaint paint;
-    paint.setColor(0xff00aa80);
-
-    // Set up the canvas's clip to match our SkClipStack.
-    ReplayClipStackVisitor visitor(canvas);
-    SkClipStack::Iter iter(stack, SkClipStack::Iter::kBottom_IterStart);
-    for (const SkClipStack::Element* element = iter.next(); element; element = iter.next()) {
-        element->replay(&visitor);
-    }
-
-    canvas->drawRect(SkRect::Make(kCoverRect), paint);
-}
-
-DEF_GM( return new WindowRectanglesGM(); )
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-#if SK_SUPPORT_GPU
-
-constexpr static int kNumWindows = 8;
-
-/**
- * Visualizes the mask (alpha or stencil) for a clip with several window rectangles. The purpose of
- * this test is to verify that window rectangles are being used during clip mask generation, and to
- * visualize where the window rectangles are placed.
- *
- * We use window rectangles when generating the clip mask because there is no need to invest time
- * defining those regions where window rectangles will be in effect during the actual draw anyway.
- *
- * This test works by filling the entire clip mask with a small checkerboard pattern before drawing
- * it, and then covering the mask with a solid color once it has been generated. The regions inside
- * window rectangles or outside the scissor should still have the initial checkerboard intact.
- */
-class WindowRectanglesMaskGM : public WindowRectanglesBaseGM {
-private:
-    constexpr static int kMaskCheckerSize = 5;
-    SkString onShortName() final { return SkString("windowrectangles_mask"); }
-    void onCoverClipStack(const SkClipStack&, SkCanvas*) final;
-    void visualizeAlphaMask(GrContext*, GrDrawContext*, const GrReducedClip&, const GrPaint&);
-    void visualizeStencilMask(GrContext*, GrDrawContext*, const GrReducedClip&, const GrPaint&);
-    void stencilCheckerboard(GrDrawContext*, bool flip);
-    void fail(SkCanvas*);
-};
-
-/**
- * Base class for GrClips that visualize a clip mask.
- */
-class MaskOnlyClipBase : public GrClip {
-private:
-    bool quickContains(const SkRect&) const final { return false; }
-    bool isRRect(const SkRect& rtBounds, SkRRect* rr, bool* aa) const final { return false; }
-    void getConservativeBounds(int width, int height, SkIRect* rect, bool* iior) const final {
-        rect->set(0, 0, width, height);
-        if (iior) {
-            *iior = false;
-        }
-    }
-};
-
-/**
- * This class clips a cover by an alpha mask. We use it to visualize the alpha clip mask.
- */
-class AlphaOnlyClip final : public MaskOnlyClipBase {
-public:
-    AlphaOnlyClip(GrTexture* mask, int x, int y) {
-        int w = mask->width(), h = mask->height();
-        SkMatrix mat = SkMatrix::MakeScale(1.f / SkIntToScalar(w), 1.f / SkIntToScalar(h));
-        mat.preTranslate(SkIntToScalar(-x), SkIntToScalar(-y));
-        fFP = GrTextureDomainEffect::Make(
-                  mask, nullptr, mat,
-                  GrTextureDomain::MakeTexelDomain(mask, SkIRect::MakeWH(w, h)),
-                  GrTextureDomain::kDecal_Mode, GrTextureParams::kNone_FilterMode,
-                  kDevice_GrCoordSet);
-
-    }
-private:
-    bool apply(GrContext*, GrDrawContext*, bool, bool, GrAppliedClip* out) const override {
-        out->addCoverageFP(fFP);
-        return true;
-    }
-    sk_sp<GrFragmentProcessor> fFP;
-};
-
-/**
- * This class clips a cover by the stencil clip bit. We use it to visualize the stencil mask.
- */
-class StencilOnlyClip final : public MaskOnlyClipBase {
-private:
-    bool apply(GrContext*, GrDrawContext*, bool, bool, GrAppliedClip* out) const override {
-        out->addStencilClip();
-        return true;
-    }
-};
-
-void WindowRectanglesMaskGM::onCoverClipStack(const SkClipStack& stack, SkCanvas* canvas) {
-    GrContext* ctx = canvas->getGrContext();
-    GrDrawContext* dc = canvas->internal_private_accessTopLayerDrawContext();
-
-    if (!ctx || !dc ||
-        dc->accessRenderTarget()->renderTargetPriv().maxWindowRectangles() < kNumWindows) {
-        this->fail(canvas);
-        return;
-    }
-
-    const GrReducedClip reducedClip(stack, SkRect::Make(kCoverRect), kNumWindows);
-
-    GrPaint paint;
-    paint.setAntiAlias(true);
-    if (!dc->isStencilBufferMultisampled()) {
-        paint.setColor4f(GrColor4f(0, 0.25f, 1, 1));
-        this->visualizeAlphaMask(ctx, dc, reducedClip, paint);
-    } else {
-        paint.setColor4f(GrColor4f(1, 0.25f, 0.25f, 1));
-        this->visualizeStencilMask(ctx, dc, reducedClip, paint);
-    }
-}
-
-void WindowRectanglesMaskGM::visualizeAlphaMask(GrContext* ctx, GrDrawContext* dc,
-                                                const GrReducedClip& reducedClip,
-                                                const GrPaint& paint) {
-    GrPixelConfig config = kRGBA_8888_GrPixelConfig;
-    if (ctx->caps()->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
-        config = kAlpha_8_GrPixelConfig;
-    }
-
-    sk_sp<GrDrawContext> maskDC(ctx->makeDrawContext(SkBackingFit::kExact, kLayerRect.width(),
-                                                     kLayerRect.height(), config, nullptr));
-    if (!maskDC ||
-        !ctx->resourceProvider()->attachStencilAttachment(maskDC->accessRenderTarget())) {
-        return;
-    }
-
-    // Draw a checker pattern into the alpha mask so we can visualize the regions left untouched by
-    // the clip mask generation.
-    this->stencilCheckerboard(maskDC.get(), true);
-    maskDC->clear(nullptr, GrColorPackA4(0xff), true);
-    maskDC->drawContextPriv().drawAndStencilRect(StencilOnlyClip(), &GrUserStencilSettings::kUnused,
-                                                 SkRegion::kDifference_Op, false, false,
-                                                 SkMatrix::I(),
-                                                 SkRect::MakeIWH(maskDC->width(), maskDC->height()));
-    reducedClip.drawAlphaClipMask(maskDC.get());
-    sk_sp<GrTexture> mask(maskDC->asTexture());
-
-    int x = kCoverRect.x() - kLayerRect.x(),
-        y = kCoverRect.y() - kLayerRect.y();
-
-    // Now visualize the alpha mask by drawing a rect over the area where it is defined. The regions
-    // inside window rectangles or outside the scissor should still have the initial checkerboard
-    // intact. (This verifies we didn't spend any time modifying those pixels in the mask.)
-    AlphaOnlyClip clip(mask.get(), x, y);
-    dc->drawRect(clip, paint, SkMatrix::I(),
-                 SkRect::Make(SkIRect::MakeXYWH(x, y, mask->width(), mask->height())));
-}
-
-void WindowRectanglesMaskGM::visualizeStencilMask(GrContext* ctx, GrDrawContext* dc,
-                                                  const GrReducedClip& reducedClip,
-                                                  const GrPaint& paint) {
-    if (!ctx->resourceProvider()->attachStencilAttachment(dc->accessRenderTarget())) {
-        return;
-    }
-
-    // Draw a checker pattern into the stencil buffer so we can visualize the regions left untouched
-    // by the clip mask generation.
-    this->stencilCheckerboard(dc, false);
-    reducedClip.drawStencilClipMask(ctx, dc, {kLayerRect.x(), kLayerRect.y()});
-
-    // Now visualize the stencil mask by covering the entire render target. The regions inside
-    // window rectangless or outside the scissor should still have the initial checkerboard intact.
-    // (This verifies we didn't spend any time modifying those pixels in the mask.)
-    dc->drawPaint(StencilOnlyClip(), paint, SkMatrix::I());
-}
-
-void WindowRectanglesMaskGM::stencilCheckerboard(GrDrawContext* dc, bool flip) {
-    constexpr static GrUserStencilSettings kSetClip(
-        GrUserStencilSettings::StaticInit<
-        0,
-        GrUserStencilTest::kAlways,
-        0,
-        GrUserStencilOp::kSetClipBit,
-        GrUserStencilOp::kKeep,
-        0>()
-    );
-
-    dc->drawContextPriv().clearStencilClip(GrFixedClip::Disabled(), false);
-
-    for (int y = 0; y < kLayerRect.height(); y += kMaskCheckerSize) {
-        for (int x = (y & 1) == flip ? 0 : kMaskCheckerSize;
-             x < kLayerRect.width(); x += 2 * kMaskCheckerSize) {
-            SkIRect checker = SkIRect::MakeXYWH(x, y, kMaskCheckerSize, kMaskCheckerSize);
-            dc->drawContextPriv().stencilRect(GrNoClip(), &kSetClip, false, SkMatrix::I(),
-                                              SkRect::Make(checker));
-        }
-    }
-}
-
-void WindowRectanglesMaskGM::fail(SkCanvas* canvas) {
-    SkPaint paint;
-    paint.setAntiAlias(true);
-    paint.setTextAlign(SkPaint::kCenter_Align);
-    paint.setTextSize(20);
-    sk_tool_utils::set_portable_typeface(&paint);
-
-    SkString errorMsg;
-    errorMsg.printf("Requires GPU with %i window rectangles", kNumWindows);
-
-    canvas->clipRect(SkRect::Make(kCoverRect));
-    canvas->clear(SK_ColorWHITE);
-    canvas->drawText(errorMsg.c_str(), errorMsg.size(), SkIntToScalar(kCoverRect.centerX()),
-                     SkIntToScalar(kCoverRect.centerY() - 10), paint);
-}
-
-DEF_GM( return new WindowRectanglesMaskGM(); )
-
-#endif
-
-}
diff --git a/gyp/gpu.gypi b/gyp/gpu.gypi
index 33142f2df3..d1a6952f13 100644
--- a/gyp/gpu.gypi
+++ b/gyp/gpu.gypi
@@ -170,7 +170,6 @@
       '<(skia_src_path)/gpu/GrResourceHandle.h',
       '<(skia_src_path)/gpu/GrResourceProvider.cpp',
       '<(skia_src_path)/gpu/GrResourceProvider.h',
-      '<(skia_src_path)/gpu/GrScissorState.h',
       '<(skia_src_path)/gpu/GrShape.cpp',
       '<(skia_src_path)/gpu/GrShape.h',
       '<(skia_src_path)/gpu/GrStencilAttachment.cpp',
@@ -205,7 +204,6 @@
       '<(skia_src_path)/gpu/GrTRecorder.h',
       '<(skia_src_path)/gpu/GrUserStencilSettings.h',
       '<(skia_src_path)/gpu/GrWindowRectangles.h',
-      '<(skia_src_path)/gpu/GrWindowRectsState.h',
       '<(skia_src_path)/gpu/GrXferProcessor.cpp',
       '<(skia_src_path)/gpu/GrYUVProvider.cpp',
       '<(skia_src_path)/gpu/GrYUVProvider.h',
diff --git a/include/gpu/GrTypesPriv.h b/include/gpu/GrTypesPriv.h
index d60fab1337..8c42d648d0 100644
--- a/include/gpu/GrTypesPriv.h
+++ b/include/gpu/GrTypesPriv.h
@@ -9,6 +9,7 @@
 #define GrTypesPriv_DEFINED
 
 #include "GrTypes.h"
+#include "SkRect.h"
 #include "SkRefCnt.h"
 
  /**
@@ -419,6 +420,32 @@ enum GrIOType {
     kRW_GrIOType
 };
 
+struct GrScissorState {
+    GrScissorState() : fEnabled(false) {}
+    GrScissorState(const SkIRect& rect) : fEnabled(true), fRect(rect) {}
+    void setDisabled() { fEnabled = false; }
+    void set(const SkIRect& rect) { fRect = rect; fEnabled = true; }
+    bool SK_WARN_UNUSED_RESULT intersect(const SkIRect& rect) {
+        if (!fEnabled) {
+            this->set(rect);
+            return true;
+        }
+        return fRect.intersect(rect);
+    }
+    bool operator==(const GrScissorState& other) const {
+        return fEnabled == other.fEnabled &&
+                (false == fEnabled || fRect == other.fRect);
+    }
+    bool operator!=(const GrScissorState& other) const { return !(*this == other); }
+
+    bool enabled() const { return fEnabled; }
+    const SkIRect& rect() const { return fRect; }
+
+private:
+    bool    fEnabled;
+    SkIRect fRect;
+};
+
 /**
 * Indicates the type of data that a GPU buffer will be used for.
 */
diff --git a/include/private/GrSurfaceProxy.h b/include/private/GrSurfaceProxy.h
index 69656fe4f5..98979ac819 100644
--- a/include/private/GrSurfaceProxy.h
+++ b/include/private/GrSurfaceProxy.h
@@ -9,7 +9,6 @@
 #define GrSurfaceProxy_DEFINED
 
 #include "GrGpuResource.h"
-#include "SkRect.h"
 
 class GrTextureProxy;
 class GrRenderTargetProxy;
diff --git a/src/gpu/GrAppliedClip.h b/src/gpu/GrAppliedClip.h
index 3e98c6cb05..c02e9d01c2 100644
--- a/src/gpu/GrAppliedClip.h
+++ b/src/gpu/GrAppliedClip.h
@@ -8,8 +8,8 @@
 #ifndef GrAppliedClip_DEFINED
 #define GrAppliedClip_DEFINED
 
-#include "GrScissorState.h"
-#include "GrWindowRectsState.h"
+#include "GrTypesPriv.h"
+#include "GrWindowRectangles.h"
 
 class GrFragmentProcessor;
 
@@ -25,7 +25,7 @@ public:
     }
 
     const GrScissorState& scissorState() const { return fScissorState; }
-    const GrWindowRectsState& windowRectsState() const { return fWindowRectsState; }
+    const GrWindowRectangles& windowRects() const { return fWindowRects; }
     GrFragmentProcessor* clipCoverageFragmentProcessor() const { return fClipCoverageFP.get(); }
     bool hasStencilClip() const { return fHasStencilClip; }
 
@@ -36,15 +36,12 @@ public:
         return fScissorState.intersect(irect) && fClippedDrawBounds.intersect(SkRect::Make(irect));
     }
 
-    void addWindowRectangles(const GrWindowRectsState& windowState) {
-        SkASSERT(!fWindowRectsState.enabled());
-        fWindowRectsState = windowState;
-    }
-
-    void addWindowRectangles(const GrWindowRectangles& windows, const SkIPoint& origin,
-                             GrWindowRectsState::Mode mode) {
-        SkASSERT(!fWindowRectsState.enabled());
-        fWindowRectsState.set(windows, origin, mode);
+    /**
+     * Adds an exclusive window rectangle to the clip. It is not currently supported to switch the
+     * windows to inclusive mode.
+     */
+    void addWindowRectangle(const SkIRect& window) {
+        fWindowRects.addWindow(window);
     }
 
     void addCoverageFP(sk_sp<GrFragmentProcessor> fp) {
@@ -65,7 +62,7 @@ public:
 
 private:
     GrScissorState             fScissorState;
-    GrWindowRectsState         fWindowRectsState;
+    GrWindowRectangles         fWindowRects;
     sk_sp<GrFragmentProcessor> fClipCoverageFP;
     bool                       fHasStencilClip;
     SkRect                     fClippedDrawBounds;
diff --git a/src/gpu/GrClipStackClip.cpp b/src/gpu/GrClipStackClip.cpp
index d6ad1d90f8..4572db5f32 100644
--- a/src/gpu/GrClipStackClip.cpp
+++ b/src/gpu/GrClipStackClip.cpp
@@ -287,14 +287,11 @@ bool GrClipStackClip::apply(GrContext* context, GrDrawContext* drawContext, bool
         return false;
     }
 
-    GrRenderTarget* rt = drawContext->accessRenderTarget();
-
     const SkScalar clipX = SkIntToScalar(fOrigin.x()),
                    clipY = SkIntToScalar(fOrigin.y());
 
     SkRect clipSpaceDevBounds = devBounds.makeOffset(clipX, clipY);
-    const GrReducedClip reducedClip(*fStack, clipSpaceDevBounds,
-                                    rt->renderTargetPriv().maxWindowRectangles());
+    const GrReducedClip reducedClip(*fStack, clipSpaceDevBounds);
 
     if (reducedClip.hasIBounds() &&
         !GrClip::IsInsideClip(reducedClip.ibounds(), clipSpaceDevBounds)) {
@@ -303,17 +300,29 @@ bool GrClipStackClip::apply(GrContext* context, GrDrawContext* drawContext, bool
         out->addScissor(scissorSpaceIBounds);
     }
 
-    if (!reducedClip.windowRectangles().empty()) {
-        out->addWindowRectangles(reducedClip.windowRectangles(), fOrigin,
-                                 GrWindowRectsState::Mode::kExclusive);
-    }
-
     if (reducedClip.elements().isEmpty()) {
         return InitialState::kAllIn == reducedClip.initialState();
     }
 
     SkASSERT(reducedClip.hasIBounds());
 
+    // Attempt to implement difference clip rects with window rectangles. This will eventually
+    // become more comprehensive.
+    if (drawContext->accessRenderTarget()->renderTargetPriv().supportsWindowRectangles() &&
+        1 == reducedClip.elements().count() && !reducedClip.requiresAA() &&
+        InitialState::kAllIn == reducedClip.initialState()) {
+        const Element* element = reducedClip.elements().head();
+        SkRegion::Op op = element->getOp();
+        if (Element::kRect_Type == element->getType() &&
+            (SkRegion::kDifference_Op == op || SkRegion::kXOR_Op == op)) {
+            SkIRect window;
+            element->getRect().round(&window);
+            window.offset(-fOrigin);
+            out->addWindowRectangle(window);
+            return true;
+        }
+    }
+
     // An element count of 4 was chosen because of the common pattern in Blink of:
     //   isect RR
     //   diff  RR
@@ -368,15 +377,12 @@ bool GrClipStackClip::apply(GrContext* context, GrDrawContext* drawContext, bool
     // use the stencil clip if we can't represent the clip as a rectangle.
     // TODO: these need to be swapped over to using a StencilAttachmentProxy
     GrStencilAttachment* stencilAttachment =
-        context->resourceProvider()->attachStencilAttachment(rt);
+        context->resourceProvider()->attachStencilAttachment(drawContext->accessRenderTarget());
     if (nullptr == stencilAttachment) {
         SkDebugf("WARNING: failed to attach stencil buffer for clip mask. Clip will be ignored.\n");
         return true;
     }
 
-    // This relies on the property that a reduced sub-rect of the last clip will contain all the
-    // relevant window rectangles that were in the last clip. This subtle requirement will go away
-    // after clipping is overhauled.
     if (stencilAttachment->mustRenderClip(reducedClip.elementsGenID(), reducedClip.ibounds(),
                                           fOrigin)) {
         reducedClip.drawStencilClipMask(context, drawContext, fOrigin);
diff --git a/src/gpu/GrDrawContext.cpp b/src/gpu/GrDrawContext.cpp
index 87252f3979..1fd113dce3 100644
--- a/src/gpu/GrDrawContext.cpp
+++ b/src/gpu/GrDrawContext.cpp
@@ -215,12 +215,9 @@ void GrDrawContextPriv::clear(const GrFixedClip& clip,
 void GrDrawContext::internalClear(const GrFixedClip& clip,
                                   const GrColor color,
                                   bool canIgnoreClip) {
-    bool isFull = false;
-    if (!clip.hasWindowRectangles()) {
-        isFull = !clip.scissorEnabled() ||
-                 (canIgnoreClip && fContext->caps()->fullClearIsFree()) ||
-                 clip.scissorRect().contains(SkIRect::MakeWH(this->width(), this->height()));
-    }
+    bool isFull = !clip.scissorEnabled() ||
+                  (canIgnoreClip && fContext->caps()->fullClearIsFree()) ||
+                  clip.scissorRect().contains(SkIRect::MakeWH(this->width(), this->height()));
 
     if (fContext->caps()->useDrawInsteadOfClear()) {
         // This works around a driver bug with clear by drawing a rect instead.
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 0117d0e1a1..3b9f1ec1a6 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -381,7 +381,7 @@ void GrDrawTarget::drawBatch(const GrPipelineBuilder& pipelineBuilder,
         sk_sp_address_as_pointer_address(pipelineBuilder.fCoverageFragmentProcessors.begin()),
         pipelineBuilder.numCoverageFragmentProcessors());
     args.fScissor = &appliedClip.scissorState();
-    args.fWindowRectsState = &appliedClip.windowRectsState();
+    args.fWindowRects = &appliedClip.windowRects();
     args.fHasStencilClip = appliedClip.hasStencilClip();
     if (!this->setupDstReadIfNecessary(pipelineBuilder, drawContext->accessRenderTarget(),
                                        clip, args.fOpts,
diff --git a/src/gpu/GrFixedClip.cpp b/src/gpu/GrFixedClip.cpp
index 7385028baf..ebdd49bbf8 100644
--- a/src/gpu/GrFixedClip.cpp
+++ b/src/gpu/GrFixedClip.cpp
@@ -10,45 +10,25 @@
 #include "GrAppliedClip.h"
 #include "GrDrawContext.h"
 
-bool GrFixedClip::quickContains(const SkRect& rect) const {
-    if (fWindowRectsState.enabled()) {
-        return false;
-    }
-    return !fScissorState.enabled() || GrClip::IsInsideClip(fScissorState.rect(), rect);
-}
-
-void GrFixedClip::getConservativeBounds(int w, int h, SkIRect* devResult, bool* iior) const {
-    devResult->setXYWH(0, 0, w, h);
+void GrFixedClip::getConservativeBounds(int width, int height, SkIRect* devResult,
+                                        bool* isIntersectionOfRects) const {
+    devResult->setXYWH(0, 0, width, height);
     if (fScissorState.enabled()) {
         if (!devResult->intersect(fScissorState.rect())) {
             devResult->setEmpty();
         }
     }
-    if (iior) {
-        *iior = true;
+    if (isIntersectionOfRects) {
+        *isIntersectionOfRects = true;
     }
 }
 
-bool GrFixedClip::isRRect(const SkRect& rtBounds, SkRRect* rr, bool* aa) const {
-    if (fWindowRectsState.enabled()) {
-        return false;
-    }
+bool GrFixedClip::apply(GrContext*, GrDrawContext* drawContext, bool isHWAntiAlias,
+                        bool hasUserStencilSettings, GrAppliedClip* out) const {
     if (fScissorState.enabled()) {
-        SkRect rect = SkRect::Make(fScissorState.rect());
-        if (!rect.intersects(rtBounds)) {
-            return false;
-        }
-        rr->setRect(rect);
-        *aa = false;
-        return true;
-    }
-    return false;
-};
-
-bool GrFixedClip::apply(GrContext*, GrDrawContext* dc, bool, bool, GrAppliedClip* out) const {
-    if (fScissorState.enabled()) {
-        SkIRect tightScissor = SkIRect::MakeWH(dc->width(), dc->height());
-        if (!tightScissor.intersect(fScissorState.rect())) {
+        SkIRect tightScissor;
+        if (!tightScissor.intersect(fScissorState.rect(),
+                                    SkIRect::MakeWH(drawContext->width(), drawContext->height()))) {
             return false;
         }
         if (IsOutsideClip(tightScissor, out->clippedDrawBounds())) {
@@ -59,10 +39,6 @@ bool GrFixedClip::apply(GrContext*, GrDrawContext* dc, bool, bool, GrAppliedClip
         }
     }
 
-    if (fWindowRectsState.enabled()) {
-        out->addWindowRectangles(fWindowRectsState);
-    }
-
     return true;
 }
 
diff --git a/src/gpu/GrFixedClip.h b/src/gpu/GrFixedClip.h
index 6fb7d23ed1..8b3a9c1c9e 100644
--- a/src/gpu/GrFixedClip.h
+++ b/src/gpu/GrFixedClip.h
@@ -9,8 +9,7 @@
 #define GrFixedClip_DEFINED
 
 #include "GrClip.h"
-#include "GrScissorState.h"
-#include "GrWindowRectsState.h"
+#include "GrTypesPriv.h"
 
 /**
  * GrFixedClip is a clip that gets implemented by fixed-function hardware.
@@ -30,26 +29,32 @@ public:
         return fScissorState.intersect(irect);
     }
 
-    const GrWindowRectsState& windowRectsState() const { return fWindowRectsState; }
-    bool hasWindowRectangles() const { return fWindowRectsState.enabled(); }
-
-    void disableWindowRectangles() { fWindowRectsState.setDisabled(); }
-
-    void setWindowRectangles(const GrWindowRectangles& windows, const SkIPoint& origin,
-                             GrWindowRectsState::Mode mode) {
-        fWindowRectsState.set(windows, origin, mode);
+    bool quickContains(const SkRect& rect) const final {
+        return !fScissorState.enabled() || GrClip::IsInsideClip(fScissorState.rect(), rect);
     }
-
-    bool quickContains(const SkRect&) const override;
-    void getConservativeBounds(int w, int h, SkIRect* devResult, bool* iior) const override;
-    bool isRRect(const SkRect& rtBounds, SkRRect* rr, bool* aa) const override;
-    bool apply(GrContext*, GrDrawContext*, bool, bool, GrAppliedClip* out) const override;
+    void getConservativeBounds(int width, int height, SkIRect* devResult,
+                               bool* isIntersectionOfRects) const final;
+
+    bool isRRect(const SkRect& rtBounds, SkRRect* rr, bool* aa) const override {
+        if (fScissorState.enabled()) {
+            SkRect rect = SkRect::Make(fScissorState.rect());
+            if (!rect.intersects(rtBounds)) {
+                return false;
+            }
+            rr->setRect(rect);
+            *aa = false;
+            return true;
+        }
+        return false;
+    };
+
+    bool apply(GrContext*, GrDrawContext*, bool useHWAA, bool hasUserStencilSettings,
+               GrAppliedClip* out) const final;
 
     static const GrFixedClip& Disabled();
 
 private:
-    GrScissorState       fScissorState;
-    GrWindowRectsState   fWindowRectsState;
+    GrScissorState   fScissorState;
 };
 
 #endif
diff --git a/src/gpu/GrPipeline.cpp b/src/gpu/GrPipeline.cpp
index 892bccd319..8fe321d667 100644
--- a/src/gpu/GrPipeline.cpp
+++ b/src/gpu/GrPipeline.cpp
@@ -27,7 +27,7 @@ GrPipeline* GrPipeline::CreateAt(void* memory, const CreateArgs& args,
     pipeline->fRenderTarget.reset(rt);
     SkASSERT(pipeline->fRenderTarget);
     pipeline->fScissorState = *args.fScissor;
-    pipeline->fWindowRectsState = *args.fWindowRectsState;
+    pipeline->fWindowRects = *args.fWindowRects;
     if (builder.hasUserStencilSettings() || args.fHasStencilClip) {
         const GrRenderTargetPriv& rtPriv = rt->renderTargetPriv();
         pipeline->fStencilSettings.reset(*builder.getUserStencil(), args.fHasStencilClip,
@@ -230,7 +230,7 @@ bool GrPipeline::AreEqual(const GrPipeline& a, const GrPipeline& b,
         a.fFragmentProcessors.count() != b.fFragmentProcessors.count() ||
         a.fNumColorProcessors != b.fNumColorProcessors ||
         a.fScissorState != b.fScissorState ||
-        !a.fWindowRectsState.cheapEqualTo(b.fWindowRectsState) ||
+        a.fWindowRects != b.fWindowRects ||
         a.fFlags != b.fFlags ||
         a.fStencilSettings != b.fStencilSettings ||
         a.fDrawFace != b.fDrawFace ||
diff --git a/src/gpu/GrPipeline.h b/src/gpu/GrPipeline.h
index 8c2f538e27..18f1a2a266 100644
--- a/src/gpu/GrPipeline.h
+++ b/src/gpu/GrPipeline.h
@@ -16,9 +16,9 @@
 #include "GrPrimitiveProcessor.h"
 #include "GrProcOptInfo.h"
 #include "GrProgramDesc.h"
-#include "GrScissorState.h"
 #include "GrStencilSettings.h"
-#include "GrWindowRectsState.h"
+#include "GrTypesPriv.h"
+#include "GrWindowRectangles.h"
 #include "SkMatrix.h"
 #include "SkRefCnt.h"
 
@@ -60,7 +60,7 @@ public:
         const GrCaps*               fCaps;
         GrPipelineOptimizations     fOpts;
         const GrScissorState*       fScissor;
-        const GrWindowRectsState*   fWindowRectsState;
+        const GrWindowRectangles*   fWindowRects;
         bool                        fHasStencilClip;
         GrXferProcessor::DstTexture fDstTexture;
     };
@@ -154,7 +154,7 @@ public:
 
     const GrScissorState& getScissorState() const { return fScissorState; }
 
-    const GrWindowRectsState& getWindowRectsState() const { return fWindowRectsState; }
+    const GrWindowRectangles& getWindowRectangles() const { return fWindowRects; }
 
     bool isHWAntialiasState() const { return SkToBool(fFlags & kHWAA_Flag); }
     bool snapVerticesToPixelCenters() const { return SkToBool(fFlags & kSnapVertices_Flag); }
@@ -223,7 +223,7 @@ private:
     typedef GrPendingProgramElement<const GrXferProcessor> ProgramXferProcessor;
     RenderTarget                        fRenderTarget;
     GrScissorState                      fScissorState;
-    GrWindowRectsState                  fWindowRectsState;
+    GrWindowRectangles                  fWindowRects;
     GrStencilSettings                   fStencilSettings;
     GrDrawFace                          fDrawFace;
     uint32_t                            fFlags;
diff --git a/src/gpu/GrReducedClip.cpp b/src/gpu/GrReducedClip.cpp
index 948f7e9947..dfc0a2651b 100644
--- a/src/gpu/GrReducedClip.cpp
+++ b/src/gpu/GrReducedClip.cpp
@@ -28,8 +28,7 @@ typedef SkClipStack::Element Element;
  * based on later intersect operations, and perhaps remove intersect-rects. We could optionally
  * take a rect in case the caller knows a bound on what is to be drawn through this clip.
  */
-GrReducedClip::GrReducedClip(const SkClipStack& stack, const SkRect& queryBounds,
-                             int maxWindowRectangles) {
+GrReducedClip::GrReducedClip(const SkClipStack& stack, const SkRect& queryBounds) {
     SkASSERT(!queryBounds.isEmpty());
     fHasIBounds = false;
 
@@ -95,15 +94,10 @@ GrReducedClip::GrReducedClip(const SkClipStack& stack, const SkRect& queryBounds
 
     // Now that we have determined the bounds to use and filtered out the trivial cases, call the
     // helper that actually walks the stack.
-    this->walkStack(stack, tighterQuery, maxWindowRectangles);
-
-    if (fWindowRects.count() < maxWindowRectangles) {
-        this->addInteriorWindowRectangles(maxWindowRectangles);
-    }
+    this->walkStack(stack, tighterQuery);
 }
 
-void GrReducedClip::walkStack(const SkClipStack& stack, const SkRect& queryBounds,
-                              int maxWindowRectangles) {
+void GrReducedClip::walkStack(const SkClipStack& stack, const SkRect& queryBounds) {
     // walk backwards until we get to:
     //  a) the beginning
     //  b) an operation that is known to make the bounds all inside/outside
@@ -162,10 +156,6 @@ void GrReducedClip::walkStack(const SkClipStack& stack, const SkRect& queryBound
                         skippable = true;
                     } else if (GrClip::IsOutsideClip(element->getBounds(), queryBounds)) {
                         skippable = true;
-                    } else if (fWindowRects.count() < maxWindowRectangles && !embiggens &&
-                               !element->isAA() && Element::kRect_Type == element->getType()) {
-                        this->addWindowRectangle(element->getRect(), false);
-                        skippable = true;
                     }
                 }
                 if (!skippable) {
@@ -430,85 +420,10 @@ void GrReducedClip::walkStack(const SkClipStack& stack, const SkRect& queryBound
     fInitialState = static_cast<GrReducedClip::InitialState>(initialTriState);
 }
 
-static bool element_is_pure_subtract(SkRegion::Op op) {
-    SkASSERT(op >= 0);
-    return op <= SkRegion::kIntersect_Op;
-
-    GR_STATIC_ASSERT(0 == SkRegion::kDifference_Op);
-    GR_STATIC_ASSERT(1 == SkRegion::kIntersect_Op);
-}
-
-void GrReducedClip::addInteriorWindowRectangles(int maxWindowRectangles) {
-    SkASSERT(fWindowRects.count() < maxWindowRectangles);
-    // Walk backwards through the element list and add window rectangles to the interiors of
-    // "difference" elements. Quit if we encounter an element that may grow the clip.
-    ElementList::Iter iter(fElements, ElementList::Iter::kTail_IterStart);
-    for (; iter.get() && element_is_pure_subtract(iter.get()->getOp()); iter.prev()) {
-        const Element* element = iter.get();
-        if (SkRegion::kDifference_Op != element->getOp()) {
-            continue;
-        }
-
-        if (Element::kRect_Type == element->getType()) {
-            SkASSERT(element->isAA());
-            this->addWindowRectangle(element->getRect(), true);
-            if (fWindowRects.count() >= maxWindowRectangles) {
-                return;
-            }
-            continue;
-        }
-
-        if (Element::kRRect_Type == element->getType()) {
-            // For round rects we add two overlapping windows in the shape of a plus.
-            const SkRRect& clipRRect = element->getRRect();
-            SkVector insetTL = clipRRect.radii(SkRRect::kUpperLeft_Corner);
-            SkVector insetBR = clipRRect.radii(SkRRect::kLowerRight_Corner);
-            if (SkRRect::kComplex_Type == clipRRect.getType()) {
-                const SkVector& insetTR = clipRRect.radii(SkRRect::kUpperRight_Corner);
-                const SkVector& insetBL = clipRRect.radii(SkRRect::kLowerLeft_Corner);
-                insetTL.fX = SkTMax(insetTL.x(), insetBL.x());
-                insetTL.fY = SkTMax(insetTL.y(), insetTR.y());
-                insetBR.fX = SkTMax(insetBR.x(), insetTR.x());
-                insetBR.fY = SkTMax(insetBR.y(), insetBL.y());
-            }
-            const SkRect& bounds = clipRRect.getBounds();
-            if (insetTL.x() + insetBR.x() >= bounds.width() ||
-                insetTL.y() + insetBR.y() >= bounds.height()) {
-                continue; // The interior "plus" is empty.
-            }
-
-            SkRect horzRect = SkRect::MakeLTRB(bounds.left(), bounds.top() + insetTL.y(),
-                                               bounds.right(), bounds.bottom() - insetBR.y());
-            this->addWindowRectangle(horzRect, element->isAA());
-            if (fWindowRects.count() >= maxWindowRectangles) {
-                return;
-            }
-
-            SkRect vertRect = SkRect::MakeLTRB(bounds.left() + insetTL.x(), bounds.top(),
-                                               bounds.right() - insetBR.x(), bounds.bottom());
-            this->addWindowRectangle(vertRect, element->isAA());
-            if (fWindowRects.count() >= maxWindowRectangles) {
-                return;
-            }
-            continue;
-        }
-    }
-}
-
-inline void GrReducedClip::addWindowRectangle(const SkRect& elementInteriorRect, bool elementIsAA) {
-    SkIRect* window = &fWindowRects.addWindow();
-    if (!elementIsAA) {
-        elementInteriorRect.round(window);
-    } else {
-        elementInteriorRect.roundIn(window);
-    }
-}
-
 inline bool GrReducedClip::intersectIBounds(const SkIRect& irect) {
     SkASSERT(fHasIBounds);
     if (!fIBounds.intersect(irect)) {
         fHasIBounds = false;
-        fWindowRects.reset();
         fElements.reset();
         fRequiresAA = false;
         fInitialState = InitialState::kAllOut;
@@ -588,11 +503,6 @@ bool GrReducedClip::drawAlphaClipMask(GrDrawContext* dc) const {
     // we populate with a rasterization of the clip.
     GrFixedClip clip(SkIRect::MakeWH(fIBounds.width(), fIBounds.height()));
 
-    if (!fWindowRects.empty()) {
-        clip.setWindowRectangles(fWindowRects, {fIBounds.left(), fIBounds.top()},
-                                 GrWindowRectsState::Mode::kExclusive);
-    }
-
     // The scratch texture that we are drawing into can be substantially larger than the mask. Only
     // clear the part that we care about.
     GrColor initialCoverage = InitialState::kAllIn == this->initialState() ? -1 : 0;
@@ -660,23 +570,18 @@ public:
     StencilClip(const SkIRect& scissorRect) : fFixedClip(scissorRect) {}
     const GrFixedClip& fixedClip() const { return fFixedClip; }
 
-    void setWindowRectangles(const GrWindowRectangles& windows, const SkIPoint& origin,
-                             GrWindowRectsState::Mode mode) {
-        fFixedClip.setWindowRectangles(windows, origin, mode);
-    }
-
 private:
-    bool quickContains(const SkRect&) const override {
+    bool quickContains(const SkRect&) const final {
         return false;
     }
-    void getConservativeBounds(int width, int height, SkIRect* bounds, bool* iior) const override {
-        fFixedClip.getConservativeBounds(width, height, bounds, iior);
+    void getConservativeBounds(int width, int height, SkIRect* devResult, bool* iior) const final {
+        fFixedClip.getConservativeBounds(width, height, devResult, iior);
     }
-    bool isRRect(const SkRect& rtBounds, SkRRect* rr, bool* aa) const override {
+    bool isRRect(const SkRect& rtBounds, SkRRect* rr, bool* aa) const final {
         return false;
     }
     bool apply(GrContext* context, GrDrawContext* drawContext, bool useHWAA,
-               bool hasUserStencilSettings, GrAppliedClip* out) const override {
+               bool hasUserStencilSettings, GrAppliedClip* out) const final {
         if (!fFixedClip.apply(context, drawContext, useHWAA, hasUserStencilSettings, out)) {
             return false;
         }
@@ -695,11 +600,6 @@ bool GrReducedClip::drawStencilClipMask(GrContext* context,
     // We set the current clip to the bounds so that our recursive draws are scissored to them.
     StencilClip stencilClip(fIBounds.makeOffset(-clipOrigin.x(), -clipOrigin.y()));
 
-    if (!fWindowRects.empty()) {
-        stencilClip.setWindowRectangles(fWindowRects, clipOrigin,
-                                        GrWindowRectsState::Mode::kExclusive);
-    }
-
     bool initialState = InitialState::kAllIn == this->initialState();
     drawContext->drawContextPriv().clearStencilClip(stencilClip.fixedClip(), initialState);
 
diff --git a/src/gpu/GrReducedClip.h b/src/gpu/GrReducedClip.h
index b8413e6df4..731d58f61c 100644
--- a/src/gpu/GrReducedClip.h
+++ b/src/gpu/GrReducedClip.h
@@ -8,7 +8,6 @@
 #ifndef GrReducedClip_DEFINED
 #define GrReducedClip_DEFINED
 
-#include "GrWindowRectangles.h"
 #include "SkClipStack.h"
 #include "SkTLList.h"
 
@@ -21,11 +20,11 @@ class GrDrawContext;
  */
 class SK_API GrReducedClip {
 public:
-    GrReducedClip(const SkClipStack&, const SkRect& queryBounds, int maxWindowRectangles = 0);
+    GrReducedClip(const SkClipStack& stack, const SkRect& queryBounds);
 
     /**
-     * If hasIBounds() is true, this is the bounding box within which the clip elements are valid.
-     * The caller must not modify any pixels outside this box. Undefined if hasIBounds() is false.
+     * If hasIBounds() is true, this is the bounding box within which the reduced clip is valid, and
+     * the caller must not modify any pixels outside this box. Undefined if hasIBounds() is false.
      */
     const SkIRect& ibounds() const { SkASSERT(fHasIBounds); return fIBounds; }
     int left() const { return this->ibounds().left(); }
@@ -39,16 +38,10 @@ public:
      */
     bool hasIBounds() const { return fHasIBounds; }
 
-    /**
-     * If nonempty, this is a set of "exclusive" windows within which the clip elements are NOT
-     * valid. The caller must not modify any pixels inside these windows.
-     */
-    const GrWindowRectangles& windowRectangles() const { return fWindowRects; }
-
     typedef SkTLList<SkClipStack::Element, 16> ElementList;
 
     /**
-     * Populated with a minimal list of elements required to fully implement the clip.
+     * Populated with a minimal list of elements that implement the clip.
      */
     const ElementList& elements() const { return fElements; }
 
@@ -74,18 +67,15 @@ public:
     bool drawStencilClipMask(GrContext*, GrDrawContext*, const SkIPoint& clipOrigin) const;
 
 private:
-    void walkStack(const SkClipStack&, const SkRect& queryBounds, int maxWindowRectangles);
-    void addInteriorWindowRectangles(int maxWindowRectangles);
-    void addWindowRectangle(const SkRect& elementInteriorRect, bool elementIsAA);
+    void walkStack(const SkClipStack&, const SkRect& queryBounds);
     bool intersectIBounds(const SkIRect&);
 
-    SkIRect              fIBounds;
-    bool                 fHasIBounds;
-    GrWindowRectangles   fWindowRects;
-    ElementList          fElements;
-    int32_t              fElementsGenID;
-    bool                 fRequiresAA;
-    InitialState         fInitialState;
+    SkIRect        fIBounds;
+    bool           fHasIBounds;
+    ElementList    fElements;
+    int32_t        fElementsGenID;
+    bool           fRequiresAA;
+    InitialState   fInitialState;
 };
 
 #endif
diff --git a/src/gpu/GrRenderTarget.cpp b/src/gpu/GrRenderTarget.cpp
index 2053a166e5..90f94b324b 100644
--- a/src/gpu/GrRenderTarget.cpp
+++ b/src/gpu/GrRenderTarget.cpp
@@ -127,8 +127,3 @@ const GrGpu::MultisampleSpecs&
 GrRenderTargetPriv::getMultisampleSpecs(const GrStencilSettings& stencil) const {
     return fRenderTarget->getGpu()->getMultisampleSpecs(fRenderTarget, stencil);
 }
-
-int GrRenderTargetPriv::maxWindowRectangles() const {
-    return (this->flags() & Flags::kWindowRectsSupport) ?
-           fRenderTarget->getGpu()->caps()->maxWindowRectangles() : 0;
-}
diff --git a/src/gpu/GrRenderTargetPriv.h b/src/gpu/GrRenderTargetPriv.h
index 698288e1cd..2c828ec59a 100644
--- a/src/gpu/GrRenderTargetPriv.h
+++ b/src/gpu/GrRenderTargetPriv.h
@@ -38,7 +38,7 @@ public:
     typedef GrRenderTarget::Flags Flags;
 
     Flags flags() const { return fRenderTarget->fFlags; }
-    int maxWindowRectangles() const;
+    bool supportsWindowRectangles() const { return this->flags() & Flags::kWindowRectsSupport; }
 
 private:
     explicit GrRenderTargetPriv(GrRenderTarget* renderTarget) : fRenderTarget(renderTarget) {}
diff --git a/src/gpu/GrScissorState.h b/src/gpu/GrScissorState.h
deleted file mode 100644
index 59ea088078..0000000000
--- a/src/gpu/GrScissorState.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef GrScissorState_DEFINED
-#define GrScissorState_DEFINED
-
-#include "SkRect.h"
-
-class GrScissorState {
-public:
-    GrScissorState() : fEnabled(false) {}
-    GrScissorState(const SkIRect& rect) : fEnabled(true), fRect(rect) {}
-    void setDisabled() { fEnabled = false; }
-    void set(const SkIRect& rect) { fRect = rect; fEnabled = true; }
-    bool SK_WARN_UNUSED_RESULT intersect(const SkIRect& rect) {
-        if (!fEnabled) {
-            this->set(rect);
-            return true;
-        }
-        return fRect.intersect(rect);
-    }
-    bool operator==(const GrScissorState& other) const {
-        return fEnabled == other.fEnabled &&
-                (false == fEnabled || fRect == other.fRect);
-    }
-    bool operator!=(const GrScissorState& other) const { return !(*this == other); }
-
-    bool enabled() const { return fEnabled; }
-    const SkIRect& rect() const { return fRect; }
-
-private:
-    bool    fEnabled;
-    SkIRect fRect;
-};
-
-#endif
diff --git a/src/gpu/GrWindowRectangles.h b/src/gpu/GrWindowRectangles.h
index 076c40d7a4..b2f6e1ab4a 100644
--- a/src/gpu/GrWindowRectangles.h
+++ b/src/gpu/GrWindowRectangles.h
@@ -15,15 +15,21 @@ class GrWindowRectangles {
 public:
     constexpr static int kMaxWindows = 8;
 
-    GrWindowRectangles() : fCount(0) {}
+    enum class Mode : bool {
+        kExclusive,
+        kInclusive
+    };
+
+    GrWindowRectangles(Mode mode = Mode::kExclusive) : fMode(mode), fCount(0) {}
     GrWindowRectangles(const GrWindowRectangles& that) : fCount(0) { *this = that; }
     ~GrWindowRectangles() { SkSafeUnref(this->rec()); }
 
-    bool empty() const { return !fCount; }
+    Mode mode() const { return fMode; }
     int count() const { return fCount; }
+    bool disabled() const { return Mode::kExclusive == fMode && !fCount; }
     const SkIRect* data() const;
 
-    void reset();
+    void reset(Mode = Mode::kExclusive);
     GrWindowRectangles& operator=(const GrWindowRectangles&);
 
     SkIRect& addWindow(const SkIRect& window) { return this->addWindow() = window; }
@@ -38,7 +44,8 @@ private:
 
     const Rec* rec() const { return fCount <= kNumLocalWindows ? nullptr : fRec; }
 
-    int fCount;
+    Mode      fMode;
+    uint8_t   fCount;
     union {
         SkIRect   fLocalWindows[kNumLocalWindows]; // If fCount <= kNumLocalWindows.
         Rec*      fRec;                            // If fCount > kNumLocalWindows.
@@ -58,13 +65,15 @@ inline const SkIRect* GrWindowRectangles::data() const {
     return fCount <= kNumLocalWindows ? fLocalWindows : fRec->fData;
 }
 
-inline void GrWindowRectangles::reset() {
+inline void GrWindowRectangles::reset(Mode mode) {
     SkSafeUnref(this->rec());
+    fMode = mode;
     fCount = 0;
 }
 
 inline GrWindowRectangles& GrWindowRectangles::operator=(const GrWindowRectangles& that) {
     SkSafeUnref(this->rec());
+    fMode = that.fMode;
     fCount = that.fCount;
     if (fCount <= kNumLocalWindows) {
         memcpy(fLocalWindows, that.fLocalWindows, fCount * sizeof(SkIRect));
@@ -89,7 +98,7 @@ inline SkIRect& GrWindowRectangles::addWindow() {
 }
 
 inline bool GrWindowRectangles::operator==(const GrWindowRectangles& that) const {
-    if (fCount != that.fCount) {
+    if (fMode != that.fMode || fCount != that.fCount) {
         return false;
     }
     if (fCount > kNumLocalWindows && fRec == that.fRec) {
diff --git a/src/gpu/GrWindowRectsState.h b/src/gpu/GrWindowRectsState.h
deleted file mode 100644
index 9d3b61b9cb..0000000000
--- a/src/gpu/GrWindowRectsState.h
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef GrWindowRectsState_DEFINED
-#define GrWindowRectsState_DEFINED
-
-#include "GrWindowRectangles.h"
-
-class GrWindowRectsState {
-public:
-    enum class Mode : bool {
-        kExclusive,
-        kInclusive
-    };
-
-    GrWindowRectsState() : fMode(Mode::kExclusive) {}
-    GrWindowRectsState(const GrWindowRectangles& windows, const SkIPoint& origin, Mode mode)
-        : fMode(mode)
-        , fOrigin(origin)
-        , fWindows(windows) {
-    }
-
-    bool enabled() const { return Mode::kInclusive == fMode || !fWindows.empty(); }
-    Mode mode() const { return fMode; }
-    const SkIPoint& origin() const { return fOrigin; }
-    const GrWindowRectangles& windows() const { return fWindows; }
-    int numWindows() const { return fWindows.count(); }
-
-    void setDisabled() {
-        fMode = Mode::kExclusive;
-        fWindows.reset();
-    }
-
-    void set(const GrWindowRectangles& windows, const SkIPoint& origin, Mode mode) {
-        fMode = mode;
-        fOrigin = origin;
-        fWindows = windows;
-    }
-
-    bool cheapEqualTo(const GrWindowRectsState& that) const {
-        if (fMode != that.fMode) {
-            return false;
-        }
-        if (!fWindows.empty() && fOrigin != that.fOrigin) {
-            return false;
-        }
-        return fWindows == that.fWindows;
-    }
-
-private:
-    Mode                 fMode;
-    SkIPoint             fOrigin;
-    GrWindowRectangles   fWindows;
-};
-
-#endif
diff --git a/src/gpu/batches/GrClearBatch.h b/src/gpu/batches/GrClearBatch.h
index 16f1ddd7f4..27e19fab6e 100644
--- a/src/gpu/batches/GrClearBatch.h
+++ b/src/gpu/batches/GrClearBatch.h
@@ -71,9 +71,6 @@ private:
         // same color.
         GrClearBatch* cb = t->cast<GrClearBatch>();
         SkASSERT(cb->fRenderTarget == fRenderTarget);
-        if (!fClip.windowRectsState().cheapEqualTo(cb->fClip.windowRectsState())) {
-            return false;
-        }
         if (cb->contains(this)) {
             fClip = cb->fClip;
             this->replaceBounds(*t);
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index e002d5101b..466af6c6ab 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -564,7 +564,7 @@ void GrGLGpu::onResetContext(uint32_t resetBits) {
 
     if (resetBits & kView_GrGLBackendState) {
         fHWScissorSettings.invalidate();
-        fHWWindowRectsState.invalidate();
+        fHWWindowRects.invalidate();
         fHWViewport.invalidate();
     }
 
@@ -1997,42 +1997,39 @@ void GrGLGpu::flushScissor(const GrScissorState& scissorState,
     this->disableScissor();
 }
 
-void GrGLGpu::flushWindowRectangles(const GrWindowRectsState& windowState,
-                                    const GrGLRenderTarget* rt) {
-    typedef GrWindowRectsState::Mode Mode;
-    SkASSERT(!windowState.enabled() || rt->renderFBOID()); // Window rects can't be used on-screen.
-    SkASSERT(windowState.numWindows() <= this->caps()->maxWindowRectangles());
+void GrGLGpu::flushWindowRectangles(const GrWindowRectangles& windows, const GrGLRenderTarget* rt) {
+    typedef GrWindowRectangles::Mode Mode;
+    SkASSERT(windows.count() <= this->caps()->maxWindowRectangles());
+    SkASSERT(windows.disabled() || rt->renderFBOID()); // Window rectangles can't be used on-screen.
 
     if (!this->caps()->maxWindowRectangles() ||
-        fHWWindowRectsState.knownEqualTo(rt->origin(), rt->getViewport(), windowState)) {
+        fHWWindowRects.equal(rt->origin(), rt->getViewport(), windows)) {
         return;
     }
 
     // This is purely a workaround for a spurious warning generated by gcc. Otherwise the above
     // assert would be sufficient. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=5912
-    int numWindows = SkTMin(windowState.numWindows(), int(GrWindowRectangles::kMaxWindows));
-    SkASSERT(windowState.numWindows() == numWindows);
+    int numWindows = SkTMin(windows.count(), int(GrWindowRectangles::kMaxWindows));
+    SkASSERT(windows.count() == numWindows);
 
     GrGLIRect glwindows[GrWindowRectangles::kMaxWindows];
-    const SkIRect* skwindows = windowState.windows().data();
-    int dx = -windowState.origin().x(), dy = -windowState.origin().y();
+    const SkIRect* skwindows = windows.data();
     for (int i = 0; i < numWindows; ++i) {
-        const SkIRect& skwindow = skwindows[i].makeOffset(dx, dy);
-        glwindows[i].setRelativeTo(rt->getViewport(), skwindow, rt->origin());
+        glwindows[i].setRelativeTo(rt->getViewport(), skwindows[i], rt->origin());
     }
 
-    GrGLenum glmode = (Mode::kExclusive == windowState.mode()) ? GR_GL_EXCLUSIVE : GR_GL_INCLUSIVE;
+    GrGLenum glmode = (Mode::kExclusive == windows.mode()) ? GR_GL_EXCLUSIVE : GR_GL_INCLUSIVE;
     GL_CALL(WindowRectangles(glmode, numWindows, glwindows->asInts()));
 
-    fHWWindowRectsState.set(rt->origin(), rt->getViewport(), windowState);
+    fHWWindowRects.set(rt->origin(), rt->getViewport(), windows);
 }
 
 void GrGLGpu::disableWindowRectangles() {
-    if (!this->caps()->maxWindowRectangles() || fHWWindowRectsState.knownDisabled()) {
+    if (!this->caps()->maxWindowRectangles() || fHWWindowRects.disabled()) {
         return;
     }
     GL_CALL(WindowRectangles(GR_GL_EXCLUSIVE, 0, nullptr));
-    fHWWindowRectsState.setDisabled();
+    fHWWindowRects.setDisabled();
 }
 
 void GrGLGpu::flushMinSampleShading(float minSampleShading) {
@@ -2082,7 +2079,7 @@ bool GrGLGpu::flushGLState(const GrPipeline& pipeline, const GrPrimitiveProcesso
     GrGLRenderTarget* glRT = static_cast<GrGLRenderTarget*>(pipeline.getRenderTarget());
     this->flushStencil(pipeline.getStencil());
     this->flushScissor(pipeline.getScissorState(), glRT->getViewport(), glRT->origin());
-    this->flushWindowRectangles(pipeline.getWindowRectsState(), glRT);
+    this->flushWindowRectangles(pipeline.getWindowRectangles(), glRT);
     this->flushHWAAState(glRT, pipeline.isHWAntialiasState(), !pipeline.getStencil().isDisabled());
 
     // This must come after textures are flushed because a texture may need
@@ -2210,7 +2207,7 @@ void GrGLGpu::clear(const GrFixedClip& clip, GrColor color, GrRenderTarget* targ
 
     this->flushRenderTarget(glRT, clip.scissorEnabled() ? &clip.scissorRect() : nullptr);
     this->flushScissor(clip.scissorState(), glRT->getViewport(), glRT->origin());
-    this->flushWindowRectangles(clip.windowRectsState(), glRT);
+    this->disableWindowRectangles();
 
     GrGLfloat r, g, b, a;
     static const GrGLfloat scale255 = 1.f / 255.f;
@@ -2274,7 +2271,7 @@ void GrGLGpu::clearStencilClip(const GrFixedClip& clip,
     this->flushRenderTarget(glRT, &SkIRect::EmptyIRect());
 
     this->flushScissor(clip.scissorState(), glRT->getViewport(), glRT->origin());
-    this->flushWindowRectangles(clip.windowRectsState(), glRT);
+    this->disableWindowRectangles();
 
     GL_CALL(StencilMask((uint32_t) clipStencilMask));
     GL_CALL(ClearStencil(value));
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index 62803ee84c..3fe4204807 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -18,7 +18,6 @@
 #include "GrGLVertexArray.h"
 #include "GrGpu.h"
 #include "GrTypes.h"
-#include "GrWindowRectsState.h"
 #include "GrXferProcessor.h"
 #include "SkTArray.h"
 #include "SkTypes.h"
@@ -315,7 +314,7 @@ private:
     // disables the scissor
     void disableScissor();
 
-    void flushWindowRectangles(const GrWindowRectsState&, const GrGLRenderTarget*);
+    void flushWindowRectangles(const GrWindowRectangles&, const GrGLRenderTarget*);
     void disableWindowRectangles();
 
     void initFSAASupport();
@@ -425,36 +424,39 @@ private:
 
     class {
     public:
-        bool valid() const { return kInvalidSurfaceOrigin != fRTOrigin; }
-        void invalidate() { fRTOrigin = kInvalidSurfaceOrigin; }
-        bool knownDisabled() const { return this->valid() && !fWindowState.enabled(); }
-        void setDisabled() { fRTOrigin = kDefault_GrSurfaceOrigin, fWindowState.setDisabled(); }
-
-        void set(GrSurfaceOrigin rtOrigin, const GrGLIRect& viewport,
-                 const GrWindowRectsState& windowState) {
-            fRTOrigin = rtOrigin;
-            fViewport = viewport;
-            fWindowState = windowState;
+        bool valid() const { return kInvalidOrigin != fOrigin; }
+        void invalidate() { fOrigin = kInvalidOrigin; }
+
+        bool disabled() const {
+            return this->valid() && Mode::kExclusive == fWindows.mode() && !fWindows.count();
         }
+        void setDisabled() { fOrigin = kDefault_GrSurfaceOrigin, fWindows.reset(); }
 
-        bool knownEqualTo(GrSurfaceOrigin rtOrigin, const GrGLIRect& viewport,
-                          const GrWindowRectsState& windowState) const {
+        bool equal(GrSurfaceOrigin org, const GrGLIRect& viewp,
+                   const GrWindowRectangles& windows) const {
             if (!this->valid()) {
                 return false;
             }
-            if (fWindowState.numWindows() && (fRTOrigin != rtOrigin || fViewport != viewport)) {
+            if (fWindows.count() && (fOrigin != org || fViewport != viewp)) {
                 return false;
             }
-            return fWindowState.cheapEqualTo(windowState);
+            return fWindows == windows;
+        }
+
+        void set(GrSurfaceOrigin org, const GrGLIRect& viewp, const GrWindowRectangles& windows) {
+            fOrigin = org;
+            fViewport = viewp;
+            fWindows = windows;
         }
 
     private:
-        enum { kInvalidSurfaceOrigin = -1 };
+        typedef GrWindowRectangles::Mode Mode;
+        enum { kInvalidOrigin = -1 };
 
-        int                  fRTOrigin;
+        int                  fOrigin;
         GrGLIRect            fViewport;
-        GrWindowRectsState   fWindowState;
-    } fHWWindowRectsState;
+        GrWindowRectangles   fWindows;
+    } fHWWindowRects;
 
     GrGLIRect                   fHWViewport;
 
diff --git a/src/gpu/vk/GrVkGpuCommandBuffer.cpp b/src/gpu/vk/GrVkGpuCommandBuffer.cpp
index e3c7cb77cc..6144cf9f8e 100644
--- a/src/gpu/vk/GrVkGpuCommandBuffer.cpp
+++ b/src/gpu/vk/GrVkGpuCommandBuffer.cpp
@@ -162,7 +162,6 @@ void GrVkGpuCommandBuffer::onClearStencilClip(GrRenderTarget* target,
                                               const GrFixedClip& clip,
                                               bool insideStencilMask) {
     SkASSERT(target);
-    SkASSERT(!clip.hasWindowRectangles());
 
     GrVkRenderTarget* vkRT = static_cast<GrVkRenderTarget*>(target);
     GrStencilAttachment* sb = target->renderTargetPriv().getStencilAttachment();
@@ -216,7 +215,6 @@ void GrVkGpuCommandBuffer::onClearStencilClip(GrRenderTarget* target,
 void GrVkGpuCommandBuffer::onClear(GrRenderTarget* target, const GrFixedClip& clip, GrColor color) {
     // parent class should never let us get here with no RT
     SkASSERT(target);
-    SkASSERT(!clip.hasWindowRectangles());
 
     VkClearColorValue vkColor;
     GrColorToRGBAFloat(color, vkColor.float32);
diff --git a/tests/ProxyTest.cpp b/tests/ProxyTest.cpp
index 367dee426a..016ce5e763 100644
--- a/tests/ProxyTest.cpp
+++ b/tests/ProxyTest.cpp
@@ -162,8 +162,7 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(WrappedProxyTest, reporter, ctxInfo) {
                         GrGpu* gpu = ctxInfo.grContext()->getGpu();
                         sk_sp<GrRenderTarget> defaultFBO(
                             gpu->wrapBackendRenderTarget(backendDesc, kBorrow_GrWrapOwnership));
-                        REPORTER_ASSERT(reporter,
-                                        !defaultFBO->renderTargetPriv().maxWindowRectangles());
+                        SkASSERT(!defaultFBO->renderTargetPriv().supportsWindowRectangles());
 
                         sk_sp<GrRenderTargetProxy> rtProxy(
                             GrRenderTargetProxy::Make(caps, defaultFBO));
@@ -179,9 +178,8 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(WrappedProxyTest, reporter, ctxInfo) {
                         desc.fFlags = kRenderTarget_GrSurfaceFlag;
                         tex.reset(provider->createTexture(desc, budgeted));
                         sk_sp<GrRenderTarget> rt(sk_ref_sp(tex->asRenderTarget()));
-                        REPORTER_ASSERT(reporter,
-                                        caps.maxWindowRectangles() ==
-                                        rt->renderTargetPriv().maxWindowRectangles());
+                        SkASSERT(caps.maxWindowRectangles() <= 0 ||
+                                rt->renderTargetPriv().supportsWindowRectangles());
 
                         sk_sp<GrRenderTargetProxy> rtProxy(GrRenderTargetProxy::Make(caps, rt));
                         check_surface(reporter, rtProxy.get(), origin,
diff --git a/tests/WindowRectanglesTest.cpp b/tests/WindowRectanglesTest.cpp
index e9545651af..d569f1d7aa 100644
--- a/tests/WindowRectanglesTest.cpp
+++ b/tests/WindowRectanglesTest.cpp
@@ -31,6 +31,7 @@ DEF_TEST(WindowRectangles, reporter) {
 
         GrWindowRectangles wr2(wr);
         REPORTER_ASSERT(reporter, wr2 == wr);
+        REPORTER_ASSERT(reporter, wr2.mode() == wr.mode());
         REPORTER_ASSERT(reporter, wr2.count() == wr.count());
         REPORTER_ASSERT(reporter, !memcmp(wr2.data(), wr.data(), i * sizeof(SkIRect)));
 
@@ -71,6 +72,21 @@ DEF_TEST(WindowRectangles, reporter) {
         REPORTER_ASSERT(reporter, !memcmp(A.data(), windowData,
                                           GrWindowRectangles::kMaxWindows * sizeof(SkIRect)));
     }
+
+    GrWindowRectangles wrI(GrWindowRectangles::Mode::kInclusive);
+    for (int i = 0; i < wr.count(); ++i) {
+        wrI.addWindow(windowData[i]);
+    }
+    REPORTER_ASSERT(reporter, wrI != wr);
+    REPORTER_ASSERT(reporter, wrI.mode() != wr.mode());
+    REPORTER_ASSERT(reporter, wrI.count() == wr.count());
+    REPORTER_ASSERT(reporter, !memcmp(wrI.data(), wr.data(), wr.count() * sizeof(SkIRect)));
+
+    wr.reset(GrWindowRectangles::Mode::kInclusive);
+    for (int i = 0; i < wrI.count(); ++i) {
+        wr.addWindow(windowData[i]);
+    }
+    REPORTER_ASSERT(reporter, wrI == wr);
 }
 
 #endif