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 91276deb8ad5bcb005ec733ce1713e3e0f543d63..4e90bdb6557d0e9dec40e75380d204548b31a64a 100644
--- a/cc/layer_tree_host.cc
+++ b/cc/layer_tree_host.cc
@@ -144,6 +144,11 @@ void LayerTreeHost::setSurfaceReady()
     m_proxy->setSurfaceReady();
 }
 
+void LayerTreeHost::setLatencyInfo(const LatencyInfo& latency_info)
+{
+    m_latencyInfo = latency_info;
+}
+
 void LayerTreeHost::initializeRenderer()
 {
     TRACE_EVENT0("cc", "LayerTreeHost::initializeRenderer");
@@ -267,6 +272,8 @@ 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)