Add latency measurement system

cc/layer_tree_host.cc

Index: cc/layer_tree_host.cc
diff --git a/cc/layer_tree_host.cc b/cc/layer_tree_host.cc
index ca5e7f103a22995846957e5af088fb1f9e84836b..6cd35c2cca677f3530c3bd6d1dcec3be7355ac49 100644
--- a/cc/layer_tree_host.cc
+++ b/cc/layer_tree_host.cc
@@ -135,6 +135,11 @@ void LayerTreeHost::setSurfaceReady()
     m_proxy->setSurfaceReady();
 }
 
+void LayerTreeHost::setLatencyInfo(const WebKit::WebLatencyInfoImpl& latency_info)
+{
+    m_latencyInfo = latency_info;
+}
+
 void LayerTreeHost::initializeRenderer()
 {
     TRACE_EVENT0("cc", "LayerTreeHost::initializeRenderer");
@@ -231,6 +236,8 @@ void LayerTreeHost::beginCommitOnImplThread(LayerTreeHostImpl* hostImpl)
 {
     DCHECK(m_proxy->isImplThread());
     TRACE_EVENT0("cc", "LayerTreeHost::commitTo");
+
+    hostImpl->setLatencyInfo(m_latencyInfo);
 }
 
 static void pushPropertiesRecursive(Layer* layer, LayerImpl* layerImpl)