cc: Allow sending BeginMainFrame before draw or 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 7f0ef897f993a3d716c226332e95829f682d8bd2..577b03d4c2c00ebe3ce24ebd1e62be1e1c04ae51 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -62,6 +62,7 @@ class CC_EXPORT SchedulerStateMachine {
     COMMIT_STATE_IDLE,
     COMMIT_STATE_FRAME_IN_PROGRESS,
     COMMIT_STATE_READY_TO_COMMIT,
+    COMMIT_STATE_WAITING_FOR_ACTIVATION,
     COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
   };
   static const char* CommitStateToString(CommitState state);
@@ -98,6 +99,7 @@ class CC_EXPORT SchedulerStateMachine {
     return commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS ||
            commit_state_ == COMMIT_STATE_READY_TO_COMMIT;
   }
+  CommitState commit_state() const { return commit_state_; }
 
   bool RedrawPending() const { return needs_redraw_; }
   bool ManageTilesPending() const { return needs_manage_tiles_; }
@@ -225,6 +227,9 @@ class CC_EXPORT SchedulerStateMachine {
   void NotifyReadyToActivate();
 
   bool has_pending_tree() const { return has_pending_tree_; }
+  bool active_tree_needs_first_draw() const {
+    return active_tree_needs_first_draw_;
+  }
 
   void DidManageTiles();
   void DidLoseOutputSurface();