Communicate audio state to renderer process on Android.

content/browser/media/audio_stream_monitor.cc

 // Copyright 2014 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/media/audio_stream_monitor.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 36 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   return is_audible_;
 }
 
 // static
 void AudioStreamMonitor::StartMonitoringStream(
     int render_process_id,
     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,
                                      render_process_id,
                                      render_frame_id,
                                      stream_id,
                                      read_power_callback));
 }
 
 // static
 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,
                                      render_process_id,
                                      render_frame_id,
                                      stream_id));
 }
 
 // static
 void AudioStreamMonitor::StartMonitoringHelper(
     int render_process_id,
     int render_frame_id,
     int stream_id,
     const ReadPowerAndClipCallback& read_power_callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   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);
   }
 }
 
 // static
 void AudioStreamMonitor::StopMonitoringHelper(int render_process_id,
                                               int render_frame_id,
                                               int stream_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(
     int render_process_id,
     int stream_id,
     const ReadPowerAndClipCallback& read_power_callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!read_power_callback.is_null());
   poll_callbacks_[StreamID(render_process_id, stream_id)] = read_power_callback;
   if (!poll_timer_.IsRunning()) {
@@ skipping 54 matching lines @@
     off_timer_.Stop();
   } else if (!off_timer_.IsRunning()) {
     off_timer_.Start(
         FROM_HERE,
         off_time - now,
         base::Bind(&AudioStreamMonitor::MaybeToggle, base::Unretained(this)));
   }
 }
 
 }  // namespace content