Add compositor support for the LatencyInfo.

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 2072b7a1d041ed44e067117e163b791209c5e60c..f334b84d11c5e5c4280ec180f2d3787386b20d37 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -343,6 +343,8 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
                                          min_page_scale_factor_,
                                          max_page_scale_factor_);
   sync_tree->SetPageScaleDelta(page_scale_delta / sent_page_scale_delta);
+  sync_tree->SetLatencyInfo(latency_info_);
+  latency_info_.Clear();
 
   host_impl->SetViewportSize(device_viewport_size_);
   host_impl->SetOverdrawBottomHeight(overdraw_bottom_height_);
@@ -680,6 +682,10 @@ void LayerTreeHost::SetVisible(bool visible) {
   proxy_->SetVisible(visible);
 }
 
+void LayerTreeHost::SetLatencyInfo(const LatencyInfo& latency_info) {
+  latency_info_.MergeWith(latency_info);
+}
+
 void LayerTreeHost::StartPageScaleAnimation(gfx::Vector2d target_offset,
                                             bool use_anchor,
                                             float scale,