cc: Always use SetNeedsBeginFrame to request the next BeginFrame

cc/output/output_surface.cc

 // Copyright (c) 2013 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/output/output_surface.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 174 matching lines @@
   base::TimeTicks alternative_deadline =
       skipped_begin_frame_args_.frame_time +
       AlternateRetroactiveBeginFramePeriod();
   if (now < skipped_begin_frame_args_.deadline ||
       now < alternative_deadline) {
     BeginFrame(skipped_begin_frame_args_);
   }
 }
 
 void OutputSurface::DidSwapBuffers() {
-  begin_frame_pending_ = false;
   pending_swap_buffers_++;
   TRACE_EVENT1("cc", "OutputSurface::DidSwapBuffers",
                "pending_swap_buffers_", pending_swap_buffers_);
   if (frame_rate_controller_)
     frame_rate_controller_->DidSwapBuffers();
   PostCheckForRetroactiveBeginFrame();
 }
 
 void OutputSurface::OnSwapBuffersComplete(const CompositorFrameAck* ack) {
   pending_swap_buffers_--;
@@ skipping 193 matching lines @@
                "discard_backbuffer", discard_backbuffer);
   // Just ignore the memory manager when it says to set the limit to zero
   // bytes. This will happen when the memory manager thinks that the renderer
   // is not visible (which the renderer knows better).
   if (policy.bytes_limit_when_visible)
     client_->SetMemoryPolicy(policy);
   client_->SetDiscardBackBufferWhenNotVisible(discard_backbuffer);
 }
 
 }  // namespace cc