Avoid memcmp on potentially unpacked structs in MailboxManager::TargetNameLess

gpu/command_buffer/service/mailbox_manager.cc

 // 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.
 
 #include "gpu/command_buffer/service/mailbox_manager.h"
 
 #include <algorithm>
 
 #include "crypto/random.h"
 #include "gpu/command_buffer/service/mailbox_synchronizer.h"
@@ skipping 83 matching lines @@
     sync_->PullTextureUpdates(this);
 }
 
 MailboxManager::TargetName::TargetName(unsigned target, const Mailbox& mailbox)
     : target(target),
       mailbox(mailbox) {
 }
 
 bool MailboxManager::TargetNameLess(const MailboxManager::TargetName& lhs,
                                     const MailboxManager::TargetName& rhs) {
-  return memcmp(&lhs, &rhs, sizeof(lhs)) < 0;
+  if (lhs.target != rhs.target)
+    return lhs.target < rhs.target;
+  return lhs.mailbox < rhs.mailbox;
 }
 
 }  // namespace gles2
 }  // namespace gpu