Add MODIFY_AUDIO_SETTINGS permission in Android manifest and implementation in audio manager.

media/audio/audio_manager_base.cc

Index: media/audio/audio_manager_base.cc
===================================================================
--- media/audio/audio_manager_base.cc	(revision 187380)
+++ media/audio/audio_manager_base.cc	(working copy)
@@ -9,6 +9,9 @@
 #include "base/command_line.h"
 #include "base/message_loop_proxy.h"
 #include "base/threading/thread.h"
+#if defined(OS_ANDROID)
+#include "jni/AudioManagerAndroid_jni.h"
+#endif
 #include "media/audio/audio_output_dispatcher_impl.h"
 #include "media/audio/audio_output_proxy.h"
 #include "media/audio/audio_output_resampler.h"
@@ -31,6 +34,11 @@
 
 static const int kMaxInputChannels = 2;
 
+#if defined(OS_ANDROID)
+static const int kAudioModeNormal = 0x00000000;
+static const int kAudioModeInCommunication = 0x00000003;
+#endif
+
 const char AudioManagerBase::kDefaultDeviceName[] = "Default";
 const char AudioManagerBase::kDefaultDeviceId[] = "default";
 
@@ -120,6 +128,11 @@
   if (stream)
     ++num_output_streams_;
 
+#if defined(OS_ANDROID)
+  if (num_input_streams_)

[Ami GONE FROM CHROMIUM, 2013/03/20 00:30:27]

I don't get it - here you're triggering off num_input_streams_ but in the
opposite below you trigger off num_output_streams_?

I expected these calls to be in MakeAudioInputStream & ReleaseInputStream,
resp., and both to be keyed off num_input_streams_.

+    SetAudioMode(kAudioModeInCommunication);
+#endif
+
   return stream;
 }
 
@@ -243,6 +256,10 @@
   // streams.
   --num_output_streams_;
   delete stream;
+#if defined(OS_ANDROID)
+  if (!num_output_streams_)
+    SetAudioMode(kAudioModeNormal);
+#endif
 }
 
 void AudioManagerBase::ReleaseInputStream(AudioInputStream* stream) {
@@ -317,6 +334,13 @@
 #endif  // defined(OS_IOS)
 }
 
+#if defined(OS_ANDROID)
+// static
+bool AudioManagerBase::RegisterAudioManager(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+#endif
+
 void AudioManagerBase::AddOutputDeviceChangeListener(
     AudioDeviceListener* listener) {
   DCHECK(message_loop_->BelongsToCurrentThread());
@@ -345,4 +369,14 @@
   return AudioParameters();
 }
 
+#if defined(OS_ANDROID)
+void AudioManagerBase::SetAudioMode(int mode) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  jobject context = base::android::GetApplicationContext();
+  DCHECK(context);
+
+  Java_AudioManagerAndroid_setMode(env, context, mode);
+}
+#endif
+
 }  // namespace media