Revert "Don't use analytic clip FPs when drawing to stencil"

This reverts commit 4c92d4aa3ed653afdff9996b90a1139ed1dc9420.

Reason for revert: Chromecast bot failure

Original change's description:
> Don't use analytic clip FPs when drawing to stencil
> 
> It doesn't make sense to multiply by coverage when drawing to stencil.
> This could theoretically work with FPs that discard and/or modify
> the sample mask, but for the time being an analytic FP means one that
> calculates a coverage value.
> 
> Bug: skia:7190
> Change-Id: Ic40cf6c19c377cba80bad458993582f5cc07022a
> Reviewed-on: https://skia-review.googlesource.com/67423
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Chris Dalton <csmartdalton@google.com>

TBR=bsalomon@google.com,robertphillips@google.com,csmartdalton@google.com

Change-Id: Ie5bd4852c201e47daee0920f5644141bee2d8a46
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:7190
Reviewed-on: https://skia-review.googlesource.com/68400
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>

1 files changed, 11 insertions, 6 deletions

diff --git a/gm/windowrectangles.cpp b/gm/windowrectangles.cpp
index 6a3f2a1eb0..b4f6562985 100644
--- a/gm/windowrectangles.cpp
+++ b/gm/windowrectangles.cpp
@@ -12,7 +12,7 @@
 
 #if SK_SUPPORT_GPU
 #  include "GrAppliedClip.h"
-#  include "GrStencilClip.h"
+#  include "GrFixedClip.h"
 #  include "GrReducedClip.h"
 #  include "GrRenderTargetContext.h"
 #  include "GrRenderTargetContextPriv.h"
@@ -166,10 +166,15 @@ private:
 };
 
 /**
- * Makes a clip object that enforces the stencil clip bit. Used to visualize the stencil mask.
+ * This class clips a cover by the stencil clip bit. We use it to visualize the stencil mask.
  */
-static GrStencilClip make_stencil_only_clip() {
-    return GrStencilClip(SkClipStack::kEmptyGenID);
+class StencilOnlyClip final : public MaskOnlyClipBase {
+private:
+    bool apply(GrContext*, GrRenderTargetContext*, bool, bool, GrAppliedClip* out,
+               SkRect* bounds) const override {
+        out->addStencilClip(SkClipStack::kEmptyGenID);
+        return true;
+    }
 };
 
 void WindowRectanglesMaskGM::onCoverClipStack(const SkClipStack& stack, SkCanvas* canvas) {
@@ -210,7 +215,7 @@ void WindowRectanglesMaskGM::visualizeAlphaMask(GrContext* ctx, GrRenderTargetCo
     // the clip mask generation.
     this->stencilCheckerboard(maskRTC.get(), true);
     maskRTC->clear(nullptr, GrColorPackA4(0xff), true);
-    maskRTC->priv().drawAndStencilRect(make_stencil_only_clip(), &GrUserStencilSettings::kUnused,
+    maskRTC->priv().drawAndStencilRect(StencilOnlyClip(), &GrUserStencilSettings::kUnused,
                                        SkRegion::kDifference_Op, false, GrAA::kNo, SkMatrix::I(),
                                        SkRect::MakeIWH(maskRTC->width(), maskRTC->height()));
     reducedClip.drawAlphaClipMask(maskRTC.get());
@@ -237,7 +242,7 @@ void WindowRectanglesMaskGM::visualizeStencilMask(GrContext* ctx, GrRenderTarget
     // Now visualize the stencil mask by covering the entire render target. 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.)
-    rtc->drawPaint(make_stencil_only_clip(), std::move(paint), SkMatrix::I());
+    rtc->drawPaint(StencilOnlyClip(), std::move(paint), SkMatrix::I());
 }
 
 void WindowRectanglesMaskGM::stencilCheckerboard(GrRenderTargetContext* rtc, bool flip) {