Enable audio/video tag in content_shell

content/browser/renderer_host/media/audio_renderer_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/renderer_host/media/audio_renderer_host.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/process.h"
 #include "base/shared_memory.h"
@@ skipping 13 matching lines @@
 }
 
 AudioRendererHost::AudioEntry::~AudioEntry() {}
 
 ///////////////////////////////////////////////////////////////////////////////
 // AudioRendererHost implementations.
 AudioRendererHost::AudioRendererHost(
     content::ResourceContext* resource_context,
     AudioManager* audio_manager)
     : resource_context_(resource_context),
-      audio_manager_(audio_manager),
-      media_observer_(NULL) {
+      audio_manager_(audio_manager) {
 }
 
 AudioRendererHost::~AudioRendererHost() {
   DCHECK(audio_entries_.empty());
 }
 
 void AudioRendererHost::OnChannelClosing() {
   BrowserMessageFilter::OnChannelClosing();
 
+  // Channel is closing, so |resource_context_| is about to become invalid.
+  resource_context_ = NULL;
+
   // Since the IPC channel is gone, close all requested audio streams.
   DeleteEntries();
 }
 
 void AudioRendererHost::OnDestruct() const {
   BrowserThread::DeleteOnIOThread::Destruct(this);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // media::AudioOutputController::EventHandler implementations.
@@ skipping 176 matching lines @@
 
   if (!entry->controller) {
     SendErrorMessage(stream_id);
     return;
   }
 
   // If we have created the controller successfully, create an entry and add it
   // to the map.
   entry->stream_id = stream_id;
   audio_entries_.insert(std::make_pair(stream_id, entry.release()));
-  GetMediaObserver()->OnSetAudioStreamStatus(this, stream_id, "created");
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamStatus(this, stream_id, "created");
 }
 
 void AudioRendererHost::OnPlayStream(int stream_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupById(stream_id);
   if (!entry) {
     SendErrorMessage(stream_id);
     return;
   }
 
   entry->controller->Play();
-  GetMediaObserver()->OnSetAudioStreamPlaying(this, stream_id, true);
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamPlaying(this, stream_id, true);
 }
 
 void AudioRendererHost::OnPauseStream(int stream_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupById(stream_id);
   if (!entry) {
     SendErrorMessage(stream_id);
     return;
   }
 
   entry->controller->Pause();
-  GetMediaObserver()->OnSetAudioStreamPlaying(this, stream_id, false);
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamPlaying(this, stream_id, false);
 }
 
 void AudioRendererHost::OnFlushStream(int stream_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupById(stream_id);
   if (!entry) {
     SendErrorMessage(stream_id);
     return;
   }
 
   entry->controller->Flush();
-  GetMediaObserver()->OnSetAudioStreamStatus(this, stream_id, "flushed");
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamStatus(this, stream_id, "flushed");
 }
 
 void AudioRendererHost::OnCloseStream(int stream_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
-  GetMediaObserver()->OnSetAudioStreamStatus(this, stream_id, "closed");
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamStatus(this, stream_id, "closed");
 
   AudioEntry* entry = LookupById(stream_id);
 
   if (entry)
     CloseAndDeleteStream(entry);
 }
 
 void AudioRendererHost::OnSetVolume(int stream_id, double volume) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntry* entry = LookupById(stream_id);
   if (!entry) {
     SendErrorMessage(stream_id);
     return;
   }
 
   // Make sure the volume is valid.
   if (volume < 0 || volume > 1.0)
     return;
   entry->controller->SetVolume(volume);
-  GetMediaObserver()->OnSetAudioStreamVolume(this, stream_id, volume);
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamVolume(this, stream_id, volume);
 }
 
 void AudioRendererHost::SendErrorMessage(int32 stream_id) {
   Send(new AudioMsg_NotifyStreamStateChanged(stream_id, kAudioStreamError));
 }
 
 void AudioRendererHost::DeleteEntries() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   for (AudioEntryMap::iterator i = audio_entries_.begin();
@@ skipping 23 matching lines @@
 void AudioRendererHost::DeleteEntry(AudioEntry* entry) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   // Delete the entry when this method goes out of scope.
   scoped_ptr<AudioEntry> entry_deleter(entry);
 
   // Erase the entry identified by |stream_id| from the map.
   audio_entries_.erase(entry->stream_id);
 
   // Notify the media observer.
-  GetMediaObserver()->OnDeleteAudioStream(this, entry->stream_id);
+  if (GetMediaObserver())
+    GetMediaObserver()->OnDeleteAudioStream(this, entry->stream_id);
 }
 
 void AudioRendererHost::DeleteEntryOnError(AudioEntry* entry) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   // Sends the error message first before we close the stream because
   // |entry| is destroyed in DeleteEntry().
   SendErrorMessage(entry->stream_id);
 
-  GetMediaObserver()->OnSetAudioStreamStatus(this, entry->stream_id, "error");
+  if (GetMediaObserver())
+    GetMediaObserver()->OnSetAudioStreamStatus(this, entry->stream_id, "error");
   CloseAndDeleteStream(entry);
 }
 
 AudioRendererHost::AudioEntry* AudioRendererHost::LookupById(int stream_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   AudioEntryMap::iterator i = audio_entries_.find(stream_id);
   if (i != audio_entries_.end() && !i->second->pending_close)
     return i->second;
   return NULL;
 }
 
 AudioRendererHost::AudioEntry* AudioRendererHost::LookupByController(
     media::AudioOutputController* controller) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   // Iterate the map of entries.
   // TODO(hclam): Implement a faster look up method.
   for (AudioEntryMap::iterator i = audio_entries_.begin();
        i != audio_entries_.end(); ++i) {
     if (!i->second->pending_close && controller == i->second->controller.get())
       return i->second;
   }
   return NULL;
 }
 
 content::MediaObserver* AudioRendererHost::GetMediaObserver() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  if (!media_observer_)
-    media_observer_ = resource_context_->GetMediaObserver();
-  return media_observer_;
+  if (resource_context_)
+    return resource_context_->GetMediaObserver();
+  return NULL;
 }