Remove IPC_BEGIN_MESSAGE_MAP_EX macro since r270839 made all bad IPCs kill their child processes.

content/browser/mime_registry_message_filter.h

 // Copyright (c) 2011 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 CONTENT_BROWSER_MIME_REGISTRY_MESSAGE_FILTER_H_
 #define CONTENT_BROWSER_MIME_REGISTRY_MESSAGE_FILTER_H_
 
 #include "base/files/file_path.h"
 #include "content/public/browser/browser_message_filter.h"
 
 namespace content {
 
 class MimeRegistryMessageFilter : public BrowserMessageFilter {
  public:
   MimeRegistryMessageFilter();
 
   virtual void OverrideThreadForMessage(
       const IPC::Message& message,
       BrowserThread::ID* thread) OVERRIDE;
-  virtual bool OnMessageReceived(const IPC::Message& message,
-                                 bool* message_was_ok) OVERRIDE;
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
  private:
   virtual ~MimeRegistryMessageFilter();
 
   void OnGetMimeTypeFromExtension(const base::FilePath::StringType& ext,
                                   std::string* mime_type);
   void OnGetMimeTypeFromFile(const base::FilePath& file_path,
                              std::string* mime_type);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MIME_REGISTRY_MESSAGE_FILTER_H_