Allow MessageFilters to restrict listening to specific message classes

content/browser/speech/speech_recognition_dispatcher_host.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 "content/browser/speech/speech_recognition_dispatcher_host.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "content/browser/browser_plugin/browser_plugin_guest.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/speech/speech_recognition_manager_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/speech_recognition_messages.h"
 #include "content/public/browser/speech_recognition_manager_delegate.h"
 #include "content/public/browser/speech_recognition_session_config.h"
 #include "content/public/browser/speech_recognition_session_context.h"
 #include "content/public/common/content_switches.h"
 
 namespace content {
+namespace {
+const uint32 kFilteredMessageClasses[] = {
+  SpeechRecognitionMsgStart
+};
+}  // namespace
 
 SpeechRecognitionDispatcherHost::SpeechRecognitionDispatcherHost(
     bool is_guest,
     int render_process_id,
     net::URLRequestContextGetter* context_getter)
-    : is_guest_(is_guest),
+    : BrowserMessageFilter(
+          kFilteredMessageClasses, arraysize(kFilteredMessageClasses)),
+      is_guest_(is_guest),
       render_process_id_(render_process_id),
       context_getter_(context_getter) {
   // Do not add any non-trivial initialization here, instead do it lazily when
   // required (e.g. see the method |SpeechRecognitionManager::GetInstance()|) or
   // add an Init() method.
 }
 
 SpeechRecognitionDispatcherHost::~SpeechRecognitionDispatcherHost() {
   SpeechRecognitionManager::GetInstance()->AbortAllSessionsForListener(this);
 }
@@ skipping 191 matching lines @@
 void SpeechRecognitionDispatcherHost::OnAudioLevelsChange(int session_id,
                                                           float volume,
                                                           float noise_volume) {
 }
 
 void SpeechRecognitionDispatcherHost::OnEnvironmentEstimationComplete(
     int session_id) {
 }
 
 }  // namespace content