Insert pinch zoom virtual viewport layers to graphics layer tree.

Source/core/platform/graphics/GraphicsLayer.cpp

Index: Source/core/platform/graphics/GraphicsLayer.cpp
diff --git a/Source/core/platform/graphics/GraphicsLayer.cpp b/Source/core/platform/graphics/GraphicsLayer.cpp
index dc61fd0eac9a4bd370f9c0d947fdf0fb703582d0..097787676a68cd0476b077e01084e90d9d718ba6 100644
--- a/Source/core/platform/graphics/GraphicsLayer.cpp
+++ b/Source/core/platform/graphics/GraphicsLayer.cpp
@@ -720,7 +720,7 @@ void GraphicsLayer::resetTrackedRepaints()
 
 void GraphicsLayer::addRepaintRect(const FloatRect& repaintRect)
 {
-    if (m_client->isTrackingRepaints()) {
+    if (m_client && m_client->isTrackingRepaints()) {

[jamesr, 2013/06/17 20:42:10]

you don't need this change, do you?

[wjmaclean, 2013/06/17 22:09:04]

No, I guess not. :-)

         FloatRect largestRepaintRect(FloatPoint(), m_size);
         largestRepaintRect.intersect(repaintRect);
         RepaintMap::iterator repaintIt = repaintRectMap().find(this);
@@ -936,7 +936,8 @@ void GraphicsLayer::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
     info.addMember(m_maskLayer, "maskLayer");
     info.addMember(m_replicaLayer, "replicaLayer");
     info.addMember(m_replicatedLayer, "replicatedLayer");
-    info.ignoreMember(m_client);
+    if (m_client)

[jamesr, 2013/06/17 20:42:10]

ditto

[wjmaclean, 2013/06/17 22:09:04]

Done.

+        info.ignoreMember(m_client);
     info.addMember(m_name, "name");
     info.addMember(m_nameBase, "nameBase");
     info.addMember(m_layer, "layer");