Unmute Tab Audio For Desktop Share

media/audio/audio_output_controller.cc

Index: media/audio/audio_output_controller.cc
diff --git a/media/audio/audio_output_controller.cc b/media/audio/audio_output_controller.cc
index d780687d1b8415aee8f6223be8497905a80b8800..3b161fe82363e34530649f587264bc8ef098ab53 100644
--- a/media/audio/audio_output_controller.cc
+++ b/media/audio/audio_output_controller.cc
@@ -119,7 +119,8 @@ void AudioOutputController::DoCreate(bool is_for_device_change) {
   if (state_ == kClosed)
     return;
 
-  DoStopCloseAndClearStream();  // Calls RemoveOutputDeviceChangeListener().
+  // Calls RemoveOutputDeviceChangeListener().
+  DoStopCloseAndClearStream(is_for_device_change);
   DCHECK_EQ(kEmpty, state_);
 
   stream_ = diverting_to_stream_ ?
@@ -132,7 +133,7 @@ void AudioOutputController::DoCreate(bool is_for_device_change) {
   }
 
   if (!stream_->Open()) {
-    DoStopCloseAndClearStream();
+    DoStopCloseAndClearStream(false);
     state_ = kError;
     handler_->OnError();
     return;
@@ -228,7 +229,7 @@ void AudioOutputController::DoClose() {
   TRACE_EVENT0("audio", "AudioOutputController::DoClose");
 
   if (state_ != kClosed) {
-    DoStopCloseAndClearStream();
+    DoStopCloseAndClearStream(false);
     sync_reader_->Close();
     state_ = kClosed;
   }
@@ -301,6 +302,14 @@ int AudioOutputController::OnMoreData(AudioBus* dest,
   sync_reader_->UpdatePendingBytes(
       total_bytes_delay + frames * params_.GetBytesPerFrame(), frames_skipped);
 
+  const int64_t kMicrosecondsPerSecond = 1000000;

[miu, 2016/05/02 20:06:13]

Delete this line, and just use base::Time::kMicrosecondsPerSecond.

[qiangchen, 2016/05/03 16:58:23]

Done.

+  const base::TimeTicks reference_time =

[miu, 2016/05/02 20:06:13]

Please wrap all these lines of code to avoid the call to TimeTicks::Now() when
there are no duplication targets (the typical case):

  if (!duplicating_targets_.empty()) {
    ...
  }

[qiangchen, 2016/05/03 16:58:23]

Done.

+      base::TimeTicks::Now() + base::TimeDelta::FromMicroseconds(
+                                   kMicrosecondsPerSecond * total_bytes_delay /
+                                   params_.GetBytesPerSecond());
+  for (auto& target : duplicating_targets_)

[miu, 2016/05/02 20:06:13]

The "auto&" doesn't help readability here. Please use "AudioPushSink*" instead.

[qiangchen, 2016/05/03 16:58:23]

Done.

+    target->OnData(*dest, reference_time);
+
   if (will_monitor_audio_levels())
     power_monitor_.Scan(*dest, frames);
 
@@ -319,7 +328,8 @@ void AudioOutputController::OnError(AudioOutputStream* stream) {
       &AudioOutputController::DoReportError, this));
 }
 
-void AudioOutputController::DoStopCloseAndClearStream() {
+void AudioOutputController::DoStopCloseAndClearStream(
+    bool is_for_device_change) {
   DCHECK(message_loop_->BelongsToCurrentThread());
 
   // Allow calling unconditionally and bail if we don't have a stream_ to close.
@@ -336,6 +346,14 @@ void AudioOutputController::DoStopCloseAndClearStream() {
 
     StopStream();
     stream_->Close();
+
+    // Only close duplicating streams when this is really a close class
+    // For device change call, duplicating streams should remain unchanged.
+    if (!is_for_device_change) {

[miu, 2016/05/02 20:06:13]

Looks like you don't need this at all. Let the guaranteed call to
StopDuplicating() guarantee that they will eventually be closed.

[qiangchen, 2016/05/03 16:58:23]

Done.

+      for (auto& target : duplicating_targets_)
+        target->Close();
+    }
+
     if (stream_ == diverting_to_stream_)
       diverting_to_stream_ = NULL;
     stream_ = NULL;
@@ -392,6 +410,18 @@ void AudioOutputController::StopDiverting() {
       FROM_HERE, base::Bind(&AudioOutputController::DoStopDiverting, this));
 }
 
+void AudioOutputController::StartDuplicating(AudioPushSink* sink) {
+  message_loop_->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioOutputController::DoStartDuplicating, this, sink));
+}
+
+void AudioOutputController::StopDuplicating(AudioPushSink* sink) {
+  message_loop_->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioOutputController::DoStopDuplicating, this, sink));
+}
+
 void AudioOutputController::DoStartDiverting(AudioOutputStream* to_stream) {
   DCHECK(message_loop_->BelongsToCurrentThread());
 
@@ -419,6 +449,32 @@ void AudioOutputController::DoStopDiverting() {
   DCHECK(!diverting_to_stream_);
 }
 
+void AudioOutputController::DoStartDuplicating(AudioPushSink* to_stream) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+  if (state_ == kClosed)
+    return;
+
+  // Already serving the stream.
+  if (duplicating_targets_.find(to_stream) != duplicating_targets_.end())
+    return;
+
+  duplicating_targets_.insert(to_stream);
+}
+
+void AudioOutputController::DoStopDuplicating(AudioPushSink* to_stream) {
+  DCHECK(message_loop_->BelongsToCurrentThread());
+
+  if (state_ == kClosed)
+    return;

[miu, 2016/05/02 20:06:13]

You should probably still call to_stream->Close() here. Otherwise, how will
|to_stream| ever be closed/destroyed? Suggestion:

  to_stream->Close();

  if (state_ == kClosed)
    return;

  // Note: no need to check whether |to_stream| is actually in the set.
  duplicating_targets_.erase(to_stream);

[qiangchen, 2016/05/03 16:58:23]

Done.

+
+  // No such stream.
+  if (duplicating_targets_.find(to_stream) == duplicating_targets_.end())
+    return;
+
+  duplicating_targets_.erase(to_stream);
+  to_stream->Close();
+}
+
 std::pair<float, bool> AudioOutputController::ReadCurrentPowerAndClip() {
   DCHECK(will_monitor_audio_levels());
   return power_monitor_.ReadCurrentPowerAndClip();