Implement difference clip rects with window rectangles

Plumbs the pipeline for window rectangles and uses them for a very
basic implementation of difference clip rects. This puts a common
Blink pattern on fast path, but we will still eventually need to make
more comprehensive use of window rectangles during clipping.

GTX 960 perf result:
                              gpu                     glinst4                 glinst16
desk_jsfiddlebigcar.skp       0.254 -> 0.177 [70%]    0.279 -> 0.197 [71%]    0.577 -> 0.196 [34%]
keymobi_sfgate_com_.skp       0.697 -> 0.513 [74%]    0.766 -> 0.451 [59%]    0.769 -> 0.597 [78%]
keymobi_blogger.skp           0.406 -> 0.314 [77%]    0.436 -> 0.292 [67%]    0.696 -> 0.319 [46%]
desk_pokemonwiki.skp          0.121 -> 0.098 [81%]     0.13 -> 0.105 [81%]    0.216 -> 0.097 [45%]
desk_wikipedia.skp            0.121 -> 0.098 [81%]     0.13 -> 0.104 [80%]    0.199 -> 0.104 [52%]
keymobi_androidpolice_co...   0.443 -> 0.382 [86%]    0.447 -> 0.398 [89%]    0.444 -> 0.396 [89%]
keymobi_booking_com_sear...   1 .15 ->  1.03 [90%]     1.17 ->  1.06 [91%]     1.17 ->  1.05 [90%]
keymobi_theverge_com.skp      0.417 -> 0.396 [95%]    0.426 -> 0.405 [95%]    0.429 ->   0.4 [93%]

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251573002

Review-Url: https://codereview.chromium.org/2251573002

1 files changed, 1 insertions, 46 deletions

diff --git a/include/gpu/GrClip.h b/include/gpu/GrClip.h
index a6a0a665bd..6457d03051 100644
--- a/include/gpu/GrClip.h
+++ b/include/gpu/GrClip.h
@@ -11,55 +11,10 @@
 #include "GrFragmentProcessor.h"
 #include "GrTypesPriv.h"
 
+class GrAppliedClip;
 class GrDrawContext;
 
 /**
- * Produced by GrClip. It provides a set of modifications to the drawing state that are used to
- * create the final GrPipeline for a GrBatch.
- */
-class GrAppliedClip : public SkNoncopyable {
-public:
-    GrAppliedClip(const SkRect& drawBounds)
-        : fHasStencilClip(false)
-        , fClippedDrawBounds(drawBounds) {
-    }
-
-    const GrScissorState& scissorState() const { return fScissorState; }
-    GrFragmentProcessor* clipCoverageFragmentProcessor() const { return fClipCoverageFP.get(); }
-    bool hasStencilClip() const { return fHasStencilClip; }
-
-    /**
-     * Intersects the applied clip with the provided rect. Returns false if the draw became empty.
-     */
-    bool addScissor(const SkIRect& irect) {
-        return fScissorState.intersect(irect) && fClippedDrawBounds.intersect(SkRect::Make(irect));
-    }
-
-    void addCoverageFP(sk_sp<GrFragmentProcessor> fp) {
-        SkASSERT(!fClipCoverageFP);
-        fClipCoverageFP = fp;
-    }
-
-    void addStencilClip() {
-        SkASSERT(!fHasStencilClip);
-        fHasStencilClip = true;
-    }
-
-    /**
-     * Returns the device bounds of the draw after clip has been applied. TODO: Ideally this would
-     * consider the combined effect of all clipping techniques in play (scissor, stencil, fp, etc.).
-     */
-    const SkRect& clippedDrawBounds() const { return fClippedDrawBounds; }
-
-private:
-    GrScissorState             fScissorState;
-    sk_sp<GrFragmentProcessor> fClipCoverageFP;
-    bool                       fHasStencilClip;
-    SkRect                     fClippedDrawBounds;
-    typedef SkNoncopyable INHERITED;
-};
-
-/**
  * GrClip is an abstract base class for applying a clip. It constructs a clip mask if necessary, and
  * fills out a GrAppliedClip instructing the caller on how to set up the draw state.
  */