[cc]: Add a BeginMainFrameNotExpectedSoon signal and route it to the RendererScheduler.

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/logging.h"
@@ skipping 317 matching lines @@
   return begin_impl_frame_args_.frame_time;
 }
 
 void Scheduler::SetupNextBeginFrameIfNeeded() {
   if (!task_runner_.get())
     return;
 
   if (state_machine_.ShouldSetNeedsBeginFrames(
           frame_source_->NeedsBeginFrames())) {
     frame_source_->SetNeedsBeginFrames(state_machine_.BeginFrameNeeded());
+    if (!frame_source_->NeedsBeginFrames()) {
+      client_->SendBeginMainFrameNoLongerRequired();
+    }
   }
 
   if (state_machine_.begin_impl_frame_state() ==
       SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE) {
     frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
   }
 
   PostBeginRetroFrameIfNeeded();
   SetupPollingMechanisms();
 }
@@ skipping 470 matching lines @@
 }
 
 bool Scheduler::IsBeginMainFrameSentOrStarted() const {
   return (state_machine_.commit_state() ==
               SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_SENT ||
           state_machine_.commit_state() ==
               SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED);
 }
 
 }  // namespace cc