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

chrome/browser/spellchecker/spellcheck_message_filter_mac.cc

 // Copyright (c) 2012 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/spellchecker/spellcheck_message_filter_mac.h"
 
 #include <algorithm>
 #include <functional>
 
 #include "base/barrier_closure.h"
@@ skipping 169 matching lines @@
 
 void SpellingRequest::OnLocalCheckCompleted(
     const std::vector<SpellCheckResult>& results) {
   // Local checking can happen on any thread - don't DCHECK thread.
   local_results_ = results;
   completion_barrier_.Run();
 }
 
 
 SpellCheckMessageFilterMac::SpellCheckMessageFilterMac(int render_process_id)
-    : BrowserMessageFilter(SpellCheckMsgStart),
-      render_process_id_(render_process_id),
+    : render_process_id_(render_process_id),
       client_(new SpellingServiceClient) {
 }
 
 void SpellCheckMessageFilterMac::OverrideThreadForMessage(
     const IPC::Message& message, BrowserThread::ID* thread) {
   if (message.type() == SpellCheckHostMsg_RequestTextCheck::ID)
     *thread = BrowserThread::UI;
 }
 
 bool SpellCheckMessageFilterMac::OnMessageReceived(const IPC::Message& message,
@@ skipping 93 matching lines @@
 }
 
 // TODO(groby): We are currently not notified of retired tags. We need
 // to track destruction of RenderViewHosts on the browser process side
 // to update our mappings when a document goes away.
 void SpellCheckMessageFilterMac::RetireDocumentTag(int route_id) {
   spellcheck_mac::CloseDocumentWithTag(ToDocumentTag(route_id));
   tag_map_.erase(route_id);
 }