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

content/shell/browser/shell_message_filter.cc

Index: content/shell/browser/shell_message_filter.cc
===================================================================
--- content/shell/browser/shell_message_filter.cc	(revision 271040)
+++ content/shell/browser/shell_message_filter.cc	(working copy)
@@ -42,10 +42,9 @@
     *thread = BrowserThread::FILE;
 }
 
-bool ShellMessageFilter::OnMessageReceived(const IPC::Message& message,
-                                           bool* message_was_ok) {
+bool ShellMessageFilter::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP_EX(ShellMessageFilter, message, *message_was_ok)
+  IPC_BEGIN_MESSAGE_MAP(ShellMessageFilter, message)
     IPC_MESSAGE_HANDLER(ShellViewHostMsg_ReadFileToString, OnReadFileToString)
     IPC_MESSAGE_HANDLER(ShellViewHostMsg_RegisterIsolatedFileSystem,
                         OnRegisterIsolatedFileSystem)