Mute audio when volume is zero on Android.

media/audio/android/audio_manager_android.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 "media/audio/android/audio_manager_android.h"
 
 #include "base/android/build_info.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 34 matching lines @@
 AudioManager* CreateAudioManager() {
   return new AudioManagerAndroid();
 }
 
 AudioManagerAndroid::AudioManagerAndroid() {
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 
   j_audio_manager_.Reset(
       Java_AudioManagerAndroid_createAudioManagerAndroid(
           base::android::AttachCurrentThread(),
-          base::android::GetApplicationContext()));
+          base::android::GetApplicationContext(),
+          reinterpret_cast<intptr_t>(this)));
   Init();
 }
 
 AudioManagerAndroid::~AudioManagerAndroid() {
   Close();
   Shutdown();
 }
 
 bool AudioManagerAndroid::HasAudioOutputDevices() {
   return true;
@@ skipping 52 matching lines @@
 AudioOutputStream* AudioManagerAndroid::MakeAudioOutputStream(
     const AudioParameters& params,
     const std::string& device_id,
     const std::string& input_device_id) {
   AudioOutputStream* stream =
       AudioManagerBase::MakeAudioOutputStream(params, std::string(),
           std::string());
   if (stream && output_stream_count() == 1) {
     SetAudioMode(kAudioModeInCommunication);
   }
+  streams_.insert(static_cast<OpenSLESOutputStream*>(stream));
   return stream;
 }
 
 AudioInputStream* AudioManagerAndroid::MakeAudioInputStream(
     const AudioParameters& params, const std::string& device_id) {
   AudioInputStream* stream =
       AudioManagerBase::MakeAudioInputStream(params, device_id);
   return stream;
 }
 
 void AudioManagerAndroid::ReleaseOutputStream(AudioOutputStream* stream) {
   AudioManagerBase::ReleaseOutputStream(stream);
   if (!output_stream_count()) {
     SetAudioMode(kAudioModeNormal);
   }
+  streams_.erase(static_cast<OpenSLESOutputStream*>(stream));
 }
 
 void AudioManagerAndroid::ReleaseInputStream(AudioInputStream* stream) {
   AudioManagerBase::ReleaseInputStream(stream);
 }
 
 AudioOutputStream* AudioManagerAndroid::MakeLinearOutputStream(
     const AudioParameters& params) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
   return new OpenSLESOutputStream(this, params);
@@ skipping 77 matching lines @@
       base::android::AttachCurrentThread(),
       j_audio_manager_.obj());
 }
 
 void AudioManagerAndroid::Close() {
   Java_AudioManagerAndroid_close(
       base::android::AttachCurrentThread(),
       j_audio_manager_.obj());
 }
 
+void AudioManagerAndroid::SetMute(JNIEnv* env, jobject obj, jboolean muted) {
+  GetMessageLoop()->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &AudioManagerAndroid::DoSetMuteOnAudioThread,
+          base::Unretained(this),
+          muted));
+}
+
+void AudioManagerAndroid::DoSetMuteOnAudioThread(bool muted) {
+  for (OutputStreams::iterator it = streams_.begin();
+       it != streams_.end(); ++it) {
+    (*it)->SetMute(muted);
+  }
+}
+
 void AudioManagerAndroid::SetAudioMode(int mode) {
   Java_AudioManagerAndroid_setMode(
       base::android::AttachCurrentThread(),
       j_audio_manager_.obj(), mode);
 }
 
 void AudioManagerAndroid::SetAudioDevice(const std::string& device_id) {
   JNIEnv* env = AttachCurrentThread();
 
   // Send the unique device ID to the Java audio manager and make the
@@ skipping 19 matching lines @@
       j_audio_manager_.obj());
 }
 
 int AudioManagerAndroid::GetAudioLowLatencyOutputFrameSize() {
   return Java_AudioManagerAndroid_getAudioLowLatencyOutputFrameSize(
       base::android::AttachCurrentThread(),
       j_audio_manager_.obj());
 }
 
 }  // namespace media