Use gpu::Mailbox in IPCs instead of std::string

ui/compositor/compositor.h

 // 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.
 
 #ifndef UI_COMPOSITOR_COMPOSITOR_H_
 #define UI_COMPOSITOR_COMPOSITOR_H_
 
 #include <string>
 
 #include "base/hash_tables.h"
@@ skipping 17 matching lines @@
 }
 
 namespace gfx {
 class GLContext;
 class GLSurface;
 class GLShareGroup;
 class Point;
 class Rect;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace WebKit {
 class WebGraphicsContext3D;
 }
 
 namespace ui {
 
 class Compositor;
 class CompositorObserver;
 class ContextProviderFromContextFactory;
 class Layer;
@@ skipping 95 matching lines @@
   Texture(bool flipped, const gfx::Size& size, float device_scale_factor);
 
   bool flipped() const { return flipped_; }
   gfx::Size size() const { return size_; }
   float device_scale_factor() const { return device_scale_factor_; }
 
   virtual unsigned int PrepareTexture() = 0;
   virtual WebKit::WebGraphicsContext3D* HostContext3D() = 0;
 
   // Replaces the texture with the texture from the specified mailbox.
-  virtual void Consume(const std::string& mailbox_name,
+  virtual void Consume(const gpu::Mailbox& mailbox_name,
                        const gfx::Size& new_size) {}
 
   // Moves the texture into the mailbox and returns the mailbox name.
   // The texture must have been previously consumed from a mailbox.
-  virtual std::string Produce();
+  virtual gpu::Mailbox Produce();
 
  protected:
   virtual ~Texture();
   gfx::Size size_;  // in pixel
 
  private:
   friend class base::RefCounted<Texture>;
 
   bool flipped_;
   float device_scale_factor_;
@@ skipping 187 matching lines @@
   bool disable_schedule_composite_;
 
   CompositorLock* compositor_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_