Use recomputed interest rect only if it changed enough

third_party/WebKit/Source/core/frame/VisualViewport.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 561 matching lines @@
 GraphicsLayer* VisualViewport::layerForHorizontalScrollbar() const
 {
     return m_overlayScrollbarHorizontal.get();
 }
 
 GraphicsLayer* VisualViewport::layerForVerticalScrollbar() const
 {
     return m_overlayScrollbarVertical.get();
 }
 
-void VisualViewport::paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect* inClip) const
+IntRect VisualViewport::computeInterestRect(const GraphicsLayer*, const IntRect&) const
+{
+    return IntRect();
+}
+
+void VisualViewport::paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect&) const
 {
 }
 
 LocalFrame* VisualViewport::mainFrame() const
 {
     return frameHost().page().mainFrame() && frameHost().page().mainFrame()->isLocalFrame() ? frameHost().page().deprecatedLocalMainFrame() : 0;
 }
 
 FloatPoint VisualViewport::clampOffsetToBoundaries(const FloatPoint& offset)
 {
@@ skipping 119 matching lines @@
     // A document is considered adapted to small screen UAs if one of these holds:
     // 1. The author specified viewport has a constrained width that is equal to
     //    the initial viewport width.
     // 2. The author has disabled viewport zoom.
     const PageScaleConstraints& constraints = frameHost().pageScaleConstraintsSet().pageDefinedConstraints();
 
     return mainFrame()->view()->layoutSize().width() == m_size.width()
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
-String VisualViewport::debugName(const GraphicsLayer* graphicsLayer)
+String VisualViewport::debugName(const GraphicsLayer* graphicsLayer) const
 {
     String name;
     if (graphicsLayer == m_innerViewportContainerLayer.get()) {
         name = "Inner Viewport Container Layer";
     } else if (graphicsLayer == m_overscrollElasticityLayer.get()) {
         name =  "Overscroll Elasticity Layer";
     } else if (graphicsLayer == m_pageScaleLayer.get()) {
         name =  "Page Scale Layer";
     } else if (graphicsLayer == m_innerViewportScrollLayer.get()) {
         name =  "Inner Viewport Scroll Layer";
     } else if (graphicsLayer == m_overlayScrollbarHorizontal.get()) {
         name =  "Overlay Scrollbar Horizontal Layer";
     } else if (graphicsLayer == m_overlayScrollbarVertical.get()) {
         name =  "Overlay Scrollbar Vertical Layer";
     } else if (graphicsLayer == m_rootTransformLayer) {
         name =  "Root Transform Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink