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 32843bc649493dc95696c0341f55aa2cae745027..bcba861ce6b87d2d96fce4adede1861035f26bb1 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;