Hook up ui::Compositor to Display's BeginFrameSource

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index bf706b6149cc5476cea675444c58ae1166c9fa3b..c3c207f6b290df7a66d0b5e2f4aba72df912dd24 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -2342,6 +2342,10 @@ void LayerTreeHostImpl::CommitVSyncParameters(base::TimeTicks timebase,
   client_->CommitVSyncParameters(timebase, interval);
 }
 
+void LayerTreeHostImpl::SetBeginFrameSource(BeginFrameSource* source) {
+  client_->SetBeginFrameSource(source);
+}
+
 void LayerTreeHostImpl::SetViewportSize(const gfx::Size& device_viewport_size) {
   if (device_viewport_size == device_viewport_size_)
     return;