cc: Always use SetNeedsBeginFrame to request the next BeginFrame

cc/output/output_surface_unittest.cc

Index: cc/output/output_surface_unittest.cc
diff --git a/cc/output/output_surface_unittest.cc b/cc/output/output_surface_unittest.cc
index 54fd3a1adc5cacf2dca5aea0ff9a3cb336ec4d7f..048ba5e4571f28669b2d4764ac6d71804006ec37 100644
--- a/cc/output/output_surface_unittest.cc
+++ b/cc/output/output_surface_unittest.cc
@@ -212,6 +212,7 @@ TEST(OutputSurfaceTest, BeginFrameEmulation) {
 
   // DidSwapBuffers should clear the pending BeginFrame.

[danakj, 2013/09/12 16:53:59]

comment should be replaced?

[brianderson, 2013/09/12 18:46:44]

Yes. I will comb the code for similar comments to remove.

   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 1);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 1);
   task_runner->RunPendingTasks();
@@ -220,6 +221,7 @@ TEST(OutputSurfaceTest, BeginFrameEmulation) {
 
   // BeginFrame should be throttled by pending swap buffers.

[danakj, 2013/09/12 16:53:59]

So if it's not tied to swap, what will throttle begin frame if swap is not
called?

[brianderson, 2013/09/12 18:46:44]

The OutputSurface will throttle sending the next BeginFrame until
SetNeedsBeginFrame(true) has been called. There are already instances where we
do not swap and the Scheduler requests another BeginFrame by calling
SetNeedsBeginFrame(true). This patch just makes it so that it is the one and
only way to get another BeginFrame.

   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 2);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 2);
   task_runner->RunPendingTasks();
@@ -284,12 +286,14 @@ TEST(OutputSurfaceTest, OptimisticAndRetroactiveBeginFrames) {
   output_surface.BeginFrameForTesting();
   EXPECT_EQ(client.begin_frame_count(), 2);
   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 3);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 1);
 
   // Optimistically injected BeginFrames should be by throttled by pending
   // swap buffers...
   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 3);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 2);
   output_surface.BeginFrameForTesting();