Add latency measurement system

cc/thread_proxy.h

Index: cc/thread_proxy.h
diff --git a/cc/thread_proxy.h b/cc/thread_proxy.h
index da4f3868eddfb01ff385e71323e828bdcb731ae8..2b2970b4fe72a34ec4b298c92b8615414065be70 100644
--- a/cc/thread_proxy.h
+++ b/cc/thread_proxy.h
@@ -65,6 +65,7 @@ public:
     virtual void postAnimationEventsToMainThreadOnImplThread(scoped_ptr<AnimationEventsVector>, base::Time wallClockTime) OVERRIDE;
     virtual bool reduceContentsTextureMemoryOnImplThread(size_t limitBytes, int priorityCutoff) OVERRIDE;
     virtual void sendManagedMemoryStats() OVERRIDE;
+    virtual void onReceivedLatencyInfo(const WebKit::WebLatencyInfoImpl& latencyInfo) OVERRIDE;
 
     // SchedulerClient implementation
     virtual void scheduledActionBeginFrame() OVERRIDE;
@@ -98,6 +99,7 @@ private:
     void setAnimationEvents(scoped_ptr<AnimationEventsVector>, base::Time wallClockTime);
     void beginContextRecreation();
     void tryToRecreateOutputSurface();
+    void receivedLatencyInfo(const WebKit::WebLatencyInfoImpl& latencyInfo);
 
     // Called on impl thread
     struct ReadbackRequest {