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

content/browser/mime_registry_message_filter.cc

Index: content/browser/mime_registry_message_filter.cc
===================================================================
--- content/browser/mime_registry_message_filter.cc	(revision 271040)
+++ content/browser/mime_registry_message_filter.cc	(working copy)
@@ -23,10 +23,9 @@
     *thread = BrowserThread::FILE;
 }
 
-bool MimeRegistryMessageFilter::OnMessageReceived(const IPC::Message& message,
-                                                  bool* message_was_ok) {
+bool MimeRegistryMessageFilter::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP_EX(MimeRegistryMessageFilter, message, *message_was_ok)
+  IPC_BEGIN_MESSAGE_MAP(MimeRegistryMessageFilter, message)
     IPC_MESSAGE_HANDLER(MimeRegistryMsg_GetMimeTypeFromExtension,
                         OnGetMimeTypeFromExtension)
     IPC_MESSAGE_HANDLER(MimeRegistryMsg_GetMimeTypeFromFile,