Revert "Allow MessageFilters to restrict listening to specific message classes"

chrome/browser/signin/principals_message_filter.cc

 // Copyright 2013 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 "chrome/browser/signin/principals_message_filter.h"
 
 #include "chrome/common/render_messages.h"
 #include "content/public/browser/browser_thread.h"
 
 PrincipalsMessageFilter::PrincipalsMessageFilter(int render_process_id)
-    : BrowserMessageFilter(ChromeMsgStart),
-      render_process_id_(render_process_id) {}
+    : render_process_id_(render_process_id) {}
 
 PrincipalsMessageFilter::~PrincipalsMessageFilter(){}
 
 void PrincipalsMessageFilter::OverrideThreadForMessage(
       const IPC::Message& message,
       content::BrowserThread::ID* thread) {
   // GetManagedAccounts message is synchronous, it must be handled in the IO
   // thread, so no need to change thread, otherwise switch to UI thread
   if (message.type() == ChromeViewHostMsg_ShowBrowserAccountManagementUI::ID)
     *thread = content::BrowserThread::UI;
@@ skipping 17 matching lines @@
 
 void PrincipalsMessageFilter::OnMsgShowBrowserAccountManagementUI(){
   // TODO(guohui)
 }
 
 void PrincipalsMessageFilter::OnMsgGetManagedAccounts(
     const GURL& url, std::vector<std::string>* managed_accounts) {
   // TODO(guohui)
 }