Implement interest rects for synchronized paint.

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 24c330e0cf5b1eb98571a12f5e62df8a30acb17f..05138d5fb54f47f74ed91b034d695599a94db75c 100644
--- a/third_party/WebKit/Source/web/PageOverlay.cpp
+++ b/third_party/WebKit/Source/web/PageOverlay.cpp
@@ -97,7 +97,12 @@ void PageOverlay::update()
     m_layer->setNeedsDisplay();
 }
 
-void PageOverlay::paintContents(const GraphicsLayer*, GraphicsContext& gc, GraphicsLayerPaintingPhase, const IntRect& inClip) const
+void PageOverlay::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& gc, GraphicsLayerPaintingPhase phase, const IntRect& inClip) const
+{
+    paintContentsIfNeeded(graphicsLayer, gc, phase);
+}
+
+void PageOverlay::paintContentsIfNeeded(const GraphicsLayer*, GraphicsContext& gc, GraphicsLayerPaintingPhase) const
 {
     ASSERT(m_layer);
     WebGraphicsContextImpl contextWrapper(gc, *this, DisplayItem::PageOverlay);