Add gpu::MailboxHolder to hold state for a gpu::Mailbox

cc/trees/layer_tree_host_unittest_delegated.cc

 // Copyright 2013 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/trees/layer_tree_host.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 117 matching lines @@
     root_pass->shared_quad_state_list.push_back(shared_quad_state.Pass());
 
     frame->render_pass_list.push_back(root_pass.Pass());
     return frame.Pass();
   }
 
   void AddTransferableResource(DelegatedFrameData* frame,
                                ResourceProvider::ResourceId resource_id) {
     TransferableResource resource;
     resource.id = resource_id;
-    resource.target = GL_TEXTURE_2D;
+    resource.mailbox_holder.texture_target = GL_TEXTURE_2D;
     frame->resource_list.push_back(resource);
   }
 
   void AddTextureQuad(DelegatedFrameData* frame,
                       ResourceProvider::ResourceId resource_id) {
     scoped_ptr<SharedQuadState> sqs = SharedQuadState::Create();
     scoped_ptr<TextureDrawQuad> quad = TextureDrawQuad::Create();
     float vertex_opacity[4] = { 1.f, 1.f, 1.f, 1.f };
     quad->SetNew(sqs.get(),
                  gfx::Rect(0, 0, 10, 10),
@@ skipping 2209 matching lines @@
   }
 
   scoped_refptr<DelegatedRendererLayer> delegated_thief_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostDelegatedTestRemoveAndChangeResources);
 
 }  // namespace
 }  // namespace cc