Revert 251207 "Use gpu::Mailbox instead of std:string in IPCs"

trunk/src/ui/compositor/compositor.cc

 // Copyright (c) 2012 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 "ui/compositor/compositor.h"
 
 #include <algorithm>
 #include <deque>
 
 #include "base/bind.h"
@@ skipping 74 matching lines @@
 
 Texture::Texture(bool flipped, const gfx::Size& size, float device_scale_factor)
     : size_(size),
       flipped_(flipped),
       device_scale_factor_(device_scale_factor) {
 }
 
 Texture::~Texture() {
 }
 
-gpu::Mailbox Texture::Produce() {
-  return gpu::Mailbox();
+std::string Texture::Produce() {
+  return std::string();
 }
 
 CompositorLock::CompositorLock(Compositor* compositor)
     : compositor_(compositor) {
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&CompositorLock::CancelLock, AsWeakPtr()),
       base::TimeDelta::FromMilliseconds(kCompositorLockTimeoutMs));
 }
 
@@ skipping 452 matching lines @@
     // CompositorObservers to be notified before starting another
     // draw cycle.
     ScheduleDraw();
   }
   FOR_EACH_OBSERVER(CompositorObserver,
                     observer_list_,
                     OnCompositingEnded(this));
 }
 
 }  // namespace ui