[cc] Forward BeginFrameAcks through DirectCFS and CFSSupport.

cc/surfaces/compositor_frame_sink_support_unittest.cc

Index: cc/surfaces/compositor_frame_sink_support_unittest.cc
diff --git a/cc/surfaces/compositor_frame_sink_support_unittest.cc b/cc/surfaces/compositor_frame_sink_support_unittest.cc
index efa9b1b2725067c9f8b253645016c0d9a2c6968a..a947a02981bf4f87019afd67671aebbf4be78c06 100644
--- a/cc/surfaces/compositor_frame_sink_support_unittest.cc
+++ b/cc/surfaces/compositor_frame_sink_support_unittest.cc
@@ -153,10 +153,13 @@ class CompositorFrameSinkSupportTest : public testing::Test,
         this, &surface_manager_, kChildFrameSink2, false /* is_root */,
         true /* handles_frame_sink_id_invalidation */,
         true /* needs_sync_points */));
+    surface_manager_.RegisterBeginFrameSource(begin_frame_source_.get(),

[Fady Samuel, 2017/03/01 19:49:07]

I guess cc::Display normally does this? Could you please add a comment about why
this is necessary in this unit test? Thanks!

[Eric Seckler, 2017/03/02 09:41:59]

Correct, normally done by the display. The other thing that seems to be missing
here is registering the hierarchy of the frame sinks (which would assign the BFS
to the other frame sinks). But since it doesn't seem to be required for the
tests, I guess we can leave it out.

Added a comment.

+                                              kDisplayFrameSink);
   }
 
   void TearDown() override {
     surface_manager_.SetDependencyTracker(nullptr);
+    surface_manager_.UnregisterBeginFrameSource(begin_frame_source_.get());
 
     // SurfaceDependencyTracker depends on this BeginFrameSource and so it must
     // be destroyed AFTER the dependency tracker is destroyed.
@@ -723,5 +726,20 @@ TEST_F(CompositorFrameSinkSupportTest, DropStaleReferencesAfterActivation) {
   EXPECT_THAT(GetChildReferences(parent_id), UnorderedElementsAre(child_id2));
 }
 
+TEST_F(CompositorFrameSinkSupportTest, PassesOnBeginFrameAcks) {
+  // Request BeginFrames.
+  display_support().SetNeedsBeginFrame(true);
+
+  // Issue a BeginFrame.
+  BeginFrameArgs args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, 0, 1);
+  begin_frame_source()->TestOnBeginFrame(args);
+
+  // Check that the support forwards our ack to the BeginFrameSource.
+  BeginFrameAck ack(0, 1, 1, 0, false);
+  display_support().DidFinishFrame(ack);
+  EXPECT_EQ(ack, begin_frame_source()->LastAckForObserver(&display_support()));
+}
+
 }  // namespace test
 }  // namespace cc