Add latency measurement system

cc/layer_tree_host.h

Index: cc/layer_tree_host.h
diff --git a/cc/layer_tree_host.h b/cc/layer_tree_host.h
index 5c1ce68d759f4fb174708b7ee6792bbce1209f50..29c1641e5017965cdcf4582ccf9898e091b9abda 100644
--- a/cc/layer_tree_host.h
+++ b/cc/layer_tree_host.h
@@ -27,6 +27,7 @@
 #include "cc/scoped_ptr_vector.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/rect.h"
+#include "webkit/compositor_bindings/web_latency_info_impl.h"
 
 #if defined(COMPILER_GCC)
 namespace BASE_HASH_NAMESPACE {
@@ -103,6 +104,7 @@ public:
     RecreateResult recreateOutputSurface();
     void didCommitAndDrawFrame() { m_client->didCommitAndDrawFrame(); }
     void didCompleteSwapBuffers() { m_client->didCompleteSwapBuffers(); }
+    void onReceivedLatencyInfo(const WebKit::WebLatencyInfoImpl& latencyInfo) { m_client->onReceivedLatencyInfo(latencyInfo); }
     void deleteContentsTexturesOnImplThread(ResourceProvider*);
     virtual void acquireLayerTextures();
     // Returns false if we should abort this frame due to initialization failure.
@@ -144,6 +146,8 @@ public:
     void setNeedsRedraw();
     bool commitRequested() const;
 
+    void setLatencyInfo(const WebKit::WebLatencyInfoImpl& latency_info);
+
     void setAnimationEvents(scoped_ptr<AnimationEventsVector>, base::Time wallClockTime);
     virtual void didAddAnimation();
 
@@ -273,6 +277,8 @@ private:
 
     static bool s_needsFilterContext;
 
+    WebKit::WebLatencyInfoImpl m_latencyInfo;
+
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };