Communicate audio state to renderer process on Android.

content/browser/media/audio_stream_monitor.cc

Index: content/browser/media/audio_stream_monitor.cc
diff --git a/content/browser/media/audio_stream_monitor.cc b/content/browser/media/audio_stream_monitor.cc
index 36e11030eb105138d231d53c7af5a0280d4ce3e4..92ec7c25c873fad07e54e482430fae6f4686976d 100644
--- a/content/browser/media/audio_stream_monitor.cc
+++ b/content/browser/media/audio_stream_monitor.cc
@@ -54,8 +54,6 @@ void AudioStreamMonitor::StartMonitoringStream(
     int render_frame_id,
     int stream_id,
     const ReadPowerAndClipCallback& read_power_callback) {
-  if (!monitoring_available())

[DaleCurtis, 2016/11/14 18:51:07]

Can we change this to power_level_monitoring() or something else more clear? The
comments in the header file also all need updates now. Likely
monitoring_available() shouldn't be public anymore.

[altimin, 2016/11/15 12:06:17]

Done. There is some logic that uses this function to prevent sleep mode when
audio is available. Sounds like legitimate usage to me.

-    return;
   BrowserThread::PostTask(BrowserThread::UI,
                           FROM_HERE,
                           base::Bind(&StartMonitoringHelper,
@@ -69,8 +67,6 @@ void AudioStreamMonitor::StartMonitoringStream(
 void AudioStreamMonitor::StopMonitoringStream(int render_process_id,
                                               int render_frame_id,
                                               int stream_id) {
-  if (!media::AudioOutputController::will_monitor_audio_levels())
-    return;
   BrowserThread::PostTask(BrowserThread::UI,
                           FROM_HERE,
                           base::Bind(&StopMonitoringHelper,
@@ -89,6 +85,14 @@ void AudioStreamMonitor::StartMonitoringHelper(
   AudioStreamMonitor* const monitor =
       AudioStreamMonitorFromRenderFrame(render_process_id, render_frame_id);
   if (monitor) {

[DaleCurtis, 2016/11/14 18:51:07]

Invert to if (!monitor) return to avoid extra nesting.

[altimin, 2016/11/15 12:06:17]

Done.

+    if (!monitoring_available()) {
+      // If audio level monitoring is not available, assume that an active

[DaleCurtis, 2016/11/14 18:51:07]

Reflow comment.

[altimin, 2016/11/15 12:06:17]

Done.

+      // stream
+      // means audio signal.
+      monitor->web_contents_->OnAudioStateChanged(true);
+      return;
+    }
+
     monitor->StartMonitoringStreamOnUIThread(
         render_process_id, stream_id, read_power_callback);
   }
@@ -101,8 +105,13 @@ void AudioStreamMonitor::StopMonitoringHelper(int render_process_id,
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   AudioStreamMonitor* const monitor =
       AudioStreamMonitorFromRenderFrame(render_process_id, render_frame_id);
-  if (monitor)
+  if (monitor) {

[DaleCurtis, 2016/11/14 18:51:07]

Invert to if (!monitor) return to avoid extra nesting.

[altimin, 2016/11/15 12:06:17]

Done.

+    if (!monitoring_available()) {
+      monitor->web_contents_->OnAudioStateChanged(false);
+      return;
+    }
     monitor->StopMonitoringStreamOnUIThread(render_process_id, stream_id);
+  }
 }
 
 void AudioStreamMonitor::StartMonitoringStreamOnUIThread(