Add latency measurement system

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index bdeea5854947eb97eed06539cdcb289f6db28eb9..3b96903214f44b652f62addf93d32ad8521bd5af 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -298,6 +298,7 @@ Compositor::Compositor(CompositorDelegate* delegate,
       device_scale_factor_(0.0f),
       last_started_frame_(0),
       last_ended_frame_(0),
+      frame_number_(0),
       disable_schedule_composite_(false),
       compositor_lock_(NULL) {
   root_web_layer_ = cc::Layer::create();
@@ -542,6 +543,21 @@ void Compositor::didCompleteSwapBuffers() {
   NotifyEnd();
 }
 
+void Compositor::onReceivedLatencyInfo(
+    const WebKit::WebLatencyInfoImpl& latencyInfo) {
+  FOR_EACH_OBSERVER(CompositorObserver,
+                    observer_list_,
+                    OnReceivedLatencyInfo(this, latencyInfo));
+}
+
+int64 Compositor::SetInputNumber(int64 input_number) {
+  WebKit::WebLatencyInfoImpl browser_latency_info;
+  browser_latency_info.rendererMainFrameNumber = ++frame_number_;
+  browser_latency_info.inputNumber = input_number;
+  host_->setLatencyInfo(browser_latency_info);
+  return frame_number_;
+}
+
 void Compositor::scheduleComposite() {
   if (!disable_schedule_composite_)
     ScheduleDraw();