Revert of Set crash key if WM_QUIT message is received on GPU message loop.

blimp/engine/app/blimp_engine_crash_keys.cc

 // Copyright 2016 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 "blimp/engine/app/blimp_engine_crash_keys.h"
 
 #include "base/debug/crash_logging.h"
 #include "base/macros.h"
 #include "components/crash/core/common/crash_keys.h"
 
@@ skipping 87 matching lines @@
       { "swdh_register_cannot_scope_url", crash_keys::kLargeSize },
       { "swdh_register_cannot_script_url", crash_keys::kLargeSize },
 
       // Temporary for https://crbug.com/619294.
       { "swdh_unregister_cannot_host_url", crash_keys::kLargeSize },
       { "swdh_unregister_cannot_scope_url", crash_keys::kLargeSize },
 
       // Temporary for https://crbug.com/630496.
       { "swdh_get_registration_cannot_host_url", crash_keys::kLargeSize },
       { "swdh_get_registration_cannot_document_url", crash_keys::kLargeSize },
-
-      // Temporary for https://crbug.com/647068.
-      { "received_quit_message", crash_keys::kSmallSize },
     };
 
   return base::debug::InitCrashKeys(engine_keys, arraysize(engine_keys),
                                     crash_keys::kChunkMaxLength);
 }
 
 }  // namespace engine
 }  // namespace blimp