[cc] Fix CompositorFrameSinkSupport BeginFrameAck interface.

content/renderer/android/synchronous_compositor_frame_sink.cc

Index: content/renderer/android/synchronous_compositor_frame_sink.cc
diff --git a/content/renderer/android/synchronous_compositor_frame_sink.cc b/content/renderer/android/synchronous_compositor_frame_sink.cc
index f95e3312157e2a7d82d2bb17191a11ad863a8837..e2345652ba0989206dc1b38ecde242219746a1f1 100644
--- a/content/renderer/android/synchronous_compositor_frame_sink.cc
+++ b/content/renderer/android/synchronous_compositor_frame_sink.cc
@@ -273,6 +273,7 @@ void SynchronousCompositorFrameSink::SubmitCompositorFrame(
     // the CompositorFrameSink client too? (We'd have to do the same for
     // hardware frames in SurfacesInstance?)
     cc::CompositorFrame embed_frame;
+    embed_frame.metadata.begin_frame_ack = frame.metadata.begin_frame_ack;
     embed_frame.render_pass_list.push_back(cc::RenderPass::Create());
 
     // The embedding RenderPass covers the entire Display's area.