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

content/browser/loader/resource_message_filter.cc

Index: content/browser/loader/resource_message_filter.cc
===================================================================
--- content/browser/loader/resource_message_filter.cc	(revision 271040)
+++ content/browser/loader/resource_message_filter.cc	(working copy)
@@ -42,10 +42,8 @@
   ResourceDispatcherHostImpl::Get()->CancelRequestsForProcess(child_id_);
 }
 
-bool ResourceMessageFilter::OnMessageReceived(const IPC::Message& message,
-                                              bool* message_was_ok) {
-  return ResourceDispatcherHostImpl::Get()->OnMessageReceived(
-      message, this, message_was_ok);
+bool ResourceMessageFilter::OnMessageReceived(const IPC::Message& message) {
+  return ResourceDispatcherHostImpl::Get()->OnMessageReceived(message, this);
 }
 
 void ResourceMessageFilter::GetContexts(