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

cc/texture_layer_unittest.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 "cc/texture_layer.h"
 
 #include <string>
 
 #include "base/callback.h"
 #include "cc/layer_tree_host.h"
@@ skipping 259 matching lines @@
       : callback_count_(0),
         commit_count_(0) {}
 
   // Make sure callback is received on main and doesn't block the impl thread.
   void ReleaseCallback(unsigned sync_point) {
     EXPECT_EQ(true, proxy()->IsMainThread());
     ++callback_count_;
   }
 
   void SetMailbox(char mailbox_char) {
+    gpu::Mailbox name;
+    memset(name.name, mailbox_char, sizeof(name.name));
     TextureMailbox mailbox(
-        std::string(64, mailbox_char),
+        name,
         base::Bind(
             &TextureLayerImplWithMailboxThreadedCallback::ReleaseCallback,
             base::Unretained(this)));
     layer_->SetTextureMailbox(mailbox);
   }
 
   virtual void beginTest() OVERRIDE {
     gfx::Size bounds(100, 100);
     root_ = Layer::Create();
     root_->SetAnchorPoint(gfx::PointF());
@@ skipping 170 matching lines @@
   EXPECT_CALL(test_data_.mock_callback_, Release(_, _)).Times(0);
   provider->DeleteResource(id);
   Mock::VerifyAndClearExpectations(&test_data_.mock_callback_);
   EXPECT_CALL(test_data_.mock_callback_, Release(test_data_.mailbox_name1_, _))
       .Times(1);
   provider->ReceiveFromParent(list);
 }
 
 }  // namespace
 }  // namespace cc