Move Mailbox from cc to gpu, and its traits to gpu/ipc

cc/transferable_resource.cc

 // Copyright 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 "base/logging.h"
 #include "cc/transferable_resource.h"
 
 namespace cc {
 
-Mailbox::Mailbox() {
-  memset(name, 0, sizeof(name));
-}
-
-bool Mailbox::isZero() const {
-  for (int i = 0; i < arraysize(name); ++i) {
-    if (name[i])
-      return false;
-  }
-  return true;
-}
-
-void Mailbox::setName(const int8* n) {
-  DCHECK(isZero() || !memcmp(name, n, sizeof(name)));
-  memcpy(name, n, sizeof(name));
-}
-
 TransferableResource::TransferableResource()
     : id(0),
       sync_point(0),
       format(0),
       filter(0) {
 }
 
 TransferableResource::~TransferableResource() {
 }
 
 }  // namespace cc