[cc] Fix CompositorFrameSinkSupport BeginFrameAck interface.

components/exo/compositor_frame_sink_holder.cc

Index: components/exo/compositor_frame_sink_holder.cc
diff --git a/components/exo/compositor_frame_sink_holder.cc b/components/exo/compositor_frame_sink_holder.cc
index 3d6e5a2716e09fa5bfb30535ffe5bfa3984df74c..c21346fc51b71d6979652fc38cf8e9ba1c5c742b 100644
--- a/components/exo/compositor_frame_sink_holder.cc
+++ b/components/exo/compositor_frame_sink_holder.cc
@@ -75,7 +75,9 @@ void CompositorFrameSinkHolder::OnNeedsBeginFrames(bool needs_begin_frames) {
 }
 
 void CompositorFrameSinkHolder::OnDidFinishFrame(const cc::BeginFrameAck& ack) {
-  // TODO(eseckler): Pass on the ack to frame_sink_.
+  // If there was damage, the submitted CompositorFrame includes the ack.
+  if (!ack.has_damage)
+    frame_sink_->BeginFrameDidNotSwap(ack);
 }
 
 ////////////////////////////////////////////////////////////////////////////////