cc: Allow sending BeginMainFrame before draw or activation

cc/scheduler/scheduler.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/scheduler/scheduler.h"
 
 #include <algorithm>
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 285 matching lines @@
         client_->ScheduledActionAcquireLayerTexturesForMainThread();
         break;
     }
   } while (action != SchedulerStateMachine::ACTION_NONE);
 
   state_machine_.AdvanceBeginFrameStateWhenNoActionsRemain();
   SetupNextBeginFrameIfNeeded();
   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 }
 
+bool Scheduler::ActiveTreeNeedsFirstDraw() const {
+  return state_machine_.active_tree_needs_first_draw();
+}
+
 bool Scheduler::WillDrawIfNeeded() const {
   return !state_machine_.PendingDrawsShouldBeAborted();
 }
 
 }  // namespace cc