Let default device in PulseAudio be the system default device

media/audio/pulse/pulse_util.cc

Index: media/audio/pulse/pulse_util.cc
diff --git a/media/audio/pulse/pulse_util.cc b/media/audio/pulse/pulse_util.cc
index 5044fa4d26eb4ab76dce0811433a8fb11d298299..7363f06b349d263d6fafff5fdec7d80a0b61cbb3 100644
--- a/media/audio/pulse/pulse_util.cc
+++ b/media/audio/pulse/pulse_util.cc
@@ -161,6 +161,31 @@ int GetHardwareLatencyInBytes(pa_stream* stream,
   } \
 } while (0)
 
+static std::string system_default_input_device;
+static std::string system_default_output_device;
+
+void SystemDefaultDeviceCallback(pa_context* context,

[Henrik Grunell, 2016/02/23 11:13:24]

Put these functions in the anonymous namespace above since they're only used in
this file.

[Henrik Grunell, 2016/02/23 11:13:24]

Add comments with brief description for these two functions.

[rchtara, 2016/02/23 14:58:51]

Done.

[rchtara, 2016/02/23 14:58:51]

I changed the cl architecture to use stream objects for storing device names.
I cannot move now the new functions I introduced to an anonymous name space
because the new functions need to be friends with the PulseAudioInputStream so
we can access the private attributes of PulseAudioInputStream from the new
functions.

+                                 const pa_server_info* info,
+                                 void* mainloop) {
+
+  system_default_input_device = info->default_source_name;

[Henrik Grunell, 2016/02/23 11:13:24]

Store the system default device names in the stream objects instead. See e.g.
https://code.google.com/p/chromium/codesearch#chromium/src/media/audio/pulse/...

Seems like that callback doesn't signal, but others do. Can you look into why
and if needed here?

[rchtara, 2016/02/23 14:58:51]

Done
In the callback,  pa_threaded_mainloop_signal is called. so the callback is
signaling.

+  system_default_output_device = info->default_sink_name;
+  pa_threaded_mainloop* pa_mainloop =
+      static_cast<pa_threaded_mainloop*>(mainloop);
+  pa_threaded_mainloop_signal(pa_mainloop, 0);
+}
+
+void GetSystemDefaultDevice(pa_threaded_mainloop* mainloop,
+                            pa_context* context) {
+  DCHECK(mainloop);
+  DCHECK(context);
+
+  pa_operation* operation = pa_context_get_server_info(
+      context, SystemDefaultDeviceCallback, mainloop);
+
+  WaitForOperationCompletion(mainloop, operation);
+}
+
 bool CreateInputStream(pa_threaded_mainloop* mainloop,
                        pa_context* context,
                        pa_stream** stream,
@@ -206,15 +231,19 @@ bool CreateInputStream(pa_threaded_mainloop* mainloop,
   buffer_attributes.minreq = buffer_size;
   buffer_attributes.prebuf = static_cast<uint32_t>(-1);
   buffer_attributes.fragsize = buffer_size;
+
   int flags = PA_STREAM_AUTO_TIMING_UPDATE |
               PA_STREAM_INTERPOLATE_TIMING |
               PA_STREAM_ADJUST_LATENCY |
               PA_STREAM_START_CORKED;
+
+  GetSystemDefaultDevice(mainloop, context);
+
   RETURN_ON_FAILURE(
       pa_stream_connect_record(
           *stream,
           device_id == AudioManagerBase::kDefaultDeviceId ?
-              NULL : device_id.c_str(),
+              system_default_input_device.c_str() : device_id.c_str(),
           &buffer_attributes,
           static_cast<pa_stream_flags_t>(flags)) == 0,
       "pa_stream_connect_record FAILED ");
@@ -327,6 +356,8 @@ bool CreateOutputStream(pa_threaded_mainloop** mainloop,
   pa_buffer_attributes.tlength = params.GetBytesPerBuffer() * 3;
   pa_buffer_attributes.fragsize = static_cast<uint32_t>(-1);
 
+  GetSystemDefaultDevice(*mainloop, *context);
+
   // Connect playback stream.  Like pa_buffer_attr, the pa_stream_flags have a
   // huge impact on the performance of the stream and were chosen through trial
   // and error.
@@ -334,7 +365,7 @@ bool CreateOutputStream(pa_threaded_mainloop** mainloop,
       pa_stream_connect_playback(
           *stream,
           device_id == AudioManagerBase::kDefaultDeviceId ?
-              NULL : device_id.c_str(),
+              system_default_output_device.c_str() : device_id.c_str(),
           &pa_buffer_attributes,
           static_cast<pa_stream_flags_t>(
               PA_STREAM_INTERPOLATE_TIMING | PA_STREAM_ADJUST_LATENCY |