cc: Start commit early and block on tree activation

cc/scheduler/scheduler_state_machine.h

Index: cc/scheduler/scheduler_state_machine.h
diff --git a/cc/scheduler/scheduler_state_machine.h b/cc/scheduler/scheduler_state_machine.h
index eb59f282f49ff1c7ec44312be69a0f7bb4b06f3e..20e39c78a7b2876eee66f9c27609bc9d947b6ef9 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -55,6 +55,7 @@ class CC_EXPORT SchedulerStateMachine {
     COMMIT_STATE_FRAME_IN_PROGRESS,
     COMMIT_STATE_READY_TO_COMMIT,
     COMMIT_STATE_WAITING_FOR_ACTIVATION,
+    COMMIT_STATE_WAITING_FOR_ACTIVATION_AND_FRAME_IN_PROGRESS,
     COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
   };
 
@@ -82,7 +83,8 @@ class CC_EXPORT SchedulerStateMachine {
   };
 
   bool CommitPending() const {
-    return commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS;
+    return commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS ||
+           commit_state_ == COMMIT_STATE_WAITING_FOR_ACTIVATION_AND_FRAME_IN_PROGRESS;
   }
 
   bool RedrawPending() const { return needs_redraw_; }