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

gpu/command_buffer/service/mailbox_manager.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 GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_H_
 
 #include <functional>
 #include <map>
 
 #include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "crypto/hmac.h"
 #include "gpu/command_buffer/common/constants.h"
 #include "gpu/gpu_export.h"
 
 // From gl2/gl2ext.h.
 #ifndef GL_MAILBOX_SIZE_CHROMIUM
 #define GL_MAILBOX_SIZE_CHROMIUM 64
 #endif
 
 typedef signed char GLbyte;
 
 namespace gpu {
+
+struct Mailbox;
+
 namespace gles2 {
 
 class TextureDefinition;
 class TextureManager;
 
 // Identifies a mailbox where a texture definition can be stored for
 // transferring textures between contexts that are not in the same context
 // group. It is a random key signed with a hash of a private key.
 struct GPU_EXPORT MailboxName {
   MailboxName();
+  explicit MailboxName(const ::gpu::Mailbox& mailbox);
   GLbyte key[GL_MAILBOX_SIZE_CHROMIUM / 2];
   GLbyte signature[GL_MAILBOX_SIZE_CHROMIUM / 2];
 };
 
 // Manages resources scoped beyond the context or context group level.
 class GPU_EXPORT MailboxManager : public base::RefCounted<MailboxManager> {
  public:
   MailboxManager();
 
   // Generate a unique mailbox name signed with the manager's private key.
@@ skipping 51 matching lines @@
   TextureDefinitionMap textures_;
 
   DISALLOW_COPY_AND_ASSIGN(MailboxManager);
 };
 }  // namespage gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_H_