gpu: Add out-of-line copy ctors for complex classes.

gpu/command_buffer/service/mailbox_manager_sync.h

 // Copyright 2014 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_SYNC_H_
 #define GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_SYNC_H_
 
 #include <map>
 #include <utility>
 
@@ skipping 61 matching lines @@
     TextureList textures_;
     TextureDefinition definition_;
 
     typedef std::map<Mailbox, scoped_refptr<TextureGroup>>
         MailboxToGroupMap;
     static base::LazyInstance<MailboxToGroupMap> mailbox_to_group_;
   };
 
   struct TextureGroupRef {
     TextureGroupRef(unsigned version, TextureGroup* group);
+    TextureGroupRef(const TextureGroupRef& other);
     ~TextureGroupRef();
     unsigned version;
     scoped_refptr<TextureGroup> group;
   };
   static void UpdateDefinitionLocked(Texture* texture,
                                      TextureGroupRef* group_ref);
 
   typedef std::map<Texture*, TextureGroupRef> TextureToGroupMap;
   TextureToGroupMap texture_to_group_;
 
   DISALLOW_COPY_AND_ASSIGN(MailboxManagerSync);
 };
 
 }  // namespage gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_MAILBOX_MANAGER_SYNC_H_