Timeline: add support for deferred canvas rasterization

Source/core/inspector/InspectorTimelineAgent.h

Index: Source/core/inspector/InspectorTimelineAgent.h
diff --git a/Source/core/inspector/InspectorTimelineAgent.h b/Source/core/inspector/InspectorTimelineAgent.h
index 2a35c564af61f63532e53df55646dbdfc7e856da..e56874332d9d20a6685f9c95efd9131eb6fdb803 100644
--- a/Source/core/inspector/InspectorTimelineAgent.h
+++ b/Source/core/inspector/InspectorTimelineAgent.h
@@ -155,6 +155,9 @@ public:
     void willComposite();
     void didComposite();
 
+    void willUpdateLayer(int layerId);
+    void didUpdateLayer();
+
     bool willWriteHTML(Document*, unsigned startLine);
     void didWriteHTML(unsigned endLine);
 
@@ -208,6 +211,8 @@ public:
     virtual void didDecodeImage() OVERRIDE;
     virtual void willResizeImage(bool shouldCache) OVERRIDE;
     virtual void didResizeImage() OVERRIDE;
+    virtual void willRasterizeCanvas() OVERRIDE;
+    virtual void didRasterizeCanvas() OVERRIDE;
 
 private:
     friend class TimelineRecordStack;
@@ -232,6 +237,8 @@ private:
     void sendEvent(PassRefPtr<InspectorObject>);
     void appendRecord(PassRefPtr<InspectorObject> data, const String& type, bool captureCallStack, Frame*);
     void pushCurrentRecord(PassRefPtr<InspectorObject>, const String& type, bool captureCallStack, Frame*, bool hasLowLevelDetails = false);
+    void enablePlatformInstrumentation();
+    void disablePlatformInstrumentation();
 
     void setDOMCounters(TypeBuilder::Timeline::TimelineEvent* record);
     void setNativeHeapStatistics(TypeBuilder::Timeline::TimelineEvent* record);