cc: Only send a BeginMainFrame inside an BeginImplFrame.

cc/scheduler/scheduler_unittest.cc

Index: cc/scheduler/scheduler_unittest.cc
diff --git a/cc/scheduler/scheduler_unittest.cc b/cc/scheduler/scheduler_unittest.cc
index 7f8d8908c8a74dff95498315592a3773050dcdc7..80d54d2306d093771f092d799be69feeb543c953 100644
--- a/cc/scheduler/scheduler_unittest.cc
+++ b/cc/scheduler/scheduler_unittest.cc
@@ -192,16 +192,20 @@ class FakeSchedulerClient : public SchedulerClient {
     EXPECT_SINGLE_ACTION("ScheduledActionBeginOutputSurfaceCreation", (*this));
     Reset();
 
-    // Finish the initial output surface creation and run the first commit.
+    // We don't see anything happening until the first impl frame.
     scheduler->DidCreateAndInitializeOutputSurface();
     scheduler->SetNeedsCommit();
-    scheduler->NotifyBeginMainFrameStarted();
-    scheduler->NotifyReadyToCommitThenActivateIfNeeded();
+    EXPECT_TRUE(needs_begin_frames());
+    EXPECT_FALSE(scheduler->BeginImplFrameDeadlinePending());
+    Reset();
 
     {
-      SCOPED_TRACE("Go through the motions to draw the commit");
+      SCOPED_TRACE("Do first frame to commit after initialize.");
       AdvanceFrame();
 
+      scheduler->NotifyBeginMainFrameStarted();
+      scheduler->NotifyReadyToCommitThenActivateIfNeeded();
+
       // Run the posted deadline task.
       EXPECT_TRUE(scheduler->BeginImplFrameDeadlinePending());
       task_runner().RunTasksWhile(ImplFrameDeadlinePending(true));