Add LatencyInfo support for Surfaces.

cc/surfaces/surface.cc

Index: cc/surfaces/surface.cc
diff --git a/cc/surfaces/surface.cc b/cc/surfaces/surface.cc
index 0e08ec4f5461c849b14bd8585c6a56476868900c..8f08d63d9275e9d77d6c1e0fa912b98524272237 100644
--- a/cc/surfaces/surface.cc
+++ b/cc/surfaces/surface.cc
@@ -33,6 +33,7 @@ Surface::~Surface() {
 
 void Surface::QueueFrame(scoped_ptr<CompositorFrame> frame,
                          const base::Closure& callback) {
+  TakeLatencyInfo(&frame->metadata.latency_info);
   scoped_ptr<CompositorFrame> previous_frame = current_frame_.Pass();
   current_frame_ = frame.Pass();
   factory_->ReceiveFromChild(
@@ -60,6 +61,19 @@ const CompositorFrame* Surface::GetEligibleFrame() {
   return current_frame_.get();
 }
 
+void Surface::TakeLatencyInfo(std::vector<ui::LatencyInfo>* latency_info) {
+  if (!current_frame_)
+    return;
+  if (latency_info->empty()) {
+    current_frame_->metadata.latency_info.swap(*latency_info);
+    return;
+  }
+  std::copy(current_frame_->metadata.latency_info.begin(),
+            current_frame_->metadata.latency_info.end(),
+            std::back_inserter(*latency_info));
+  current_frame_->metadata.latency_info.clear();
+}
+
 void Surface::RunDrawCallbacks() {
   if (!draw_callback_.is_null()) {
     base::Closure callback = draw_callback_;