Use recomputed interest rect only if it changed enough

third_party/WebKit/Source/web/PageOverlay.cpp

Index: third_party/WebKit/Source/web/PageOverlay.cpp
diff --git a/third_party/WebKit/Source/web/PageOverlay.cpp b/third_party/WebKit/Source/web/PageOverlay.cpp
index 86ae8472837d8a49b0b163c48c71e5694fc616f1..cf837ab9e73e963ec6e34df54a3e8a3e77bd4747 100644
--- a/third_party/WebKit/Source/web/PageOverlay.cpp
+++ b/third_party/WebKit/Source/web/PageOverlay.cpp
@@ -96,13 +96,18 @@ void PageOverlay::update()
     m_layer->setNeedsDisplay();
 }
 
-void PageOverlay::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& gc, GraphicsLayerPaintingPhase phase, const IntRect* inClip) const
+IntRect PageOverlay::computeInterestRect(const GraphicsLayer* graphicsLayer, const IntRect&) const
+{
+    return IntRect(IntPoint(), expandedIntSize(m_layer->size()));
+}
+
+void PageOverlay::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& gc, GraphicsLayerPaintingPhase phase, const IntRect& interestRect) const
 {
     ASSERT(m_layer);
-    m_delegate->paintPageOverlay(*this, gc, expandedIntSize(m_layer->size()));
+    m_delegate->paintPageOverlay(*this, gc, interestRect.size());
 }
 
-String PageOverlay::debugName(const GraphicsLayer*)
+String PageOverlay::debugName(const GraphicsLayer*) const
 {
     return "WebViewImpl Page Overlay Content Layer";
 }