Use recomputed interest rect only if it changed enough

third_party/WebKit/Source/platform/graphics/GraphicsLayerTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 31 matching lines @@
 #include "public/platform/WebUnitTestSupport.h"
 #include "wtf/PassOwnPtr.h"
 #include <gtest/gtest.h>
 
 namespace blink {
 
 namespace {
 
 class MockGraphicsLayerClient : public GraphicsLayerClient {
 public:
-    void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect* inClip) const override { }
-    String debugName(const GraphicsLayer*) override { return String(); }
+    IntRect computeInterestRect(const GraphicsLayer*, const IntRect&) const { return IntRect(); }
+    void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect&) const override { }
+    String debugName(const GraphicsLayer*) const override { return String(); }
 };
 
 class GraphicsLayerForTesting : public GraphicsLayer {
 public:
     explicit GraphicsLayerForTesting(GraphicsLayerClient* client)
         : GraphicsLayer(client) { }
 };
 
 } // anonymous namespace
 
@@ skipping 167 matching lines @@
 
     WebDoublePoint scrollPosition(7, 9);
     m_platformLayer->setScrollPositionDouble(scrollPosition);
     m_graphicsLayer->didScroll();
 
     EXPECT_FLOAT_EQ(scrollPosition.x, scrollableArea->scrollPositionDouble().x());
     EXPECT_FLOAT_EQ(scrollPosition.y, scrollableArea->scrollPositionDouble().y());
 }
 
 } // namespace blink