Add a mojo implementation of AudioOutputIPC.

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 4ee6d4f7fd0e4ea1051de524511a318b56ae359d..26b015753c2e1699be137f37e8a8cc837f008a47 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -21,6 +21,7 @@
 #include "base/metrics/field_trial.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/observer_list.h"
+#include "base/optional.h"
 #include "base/strings/string16.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
@@ -40,6 +41,7 @@
 #include "content/public/renderer/render_thread.h"
 #include "content/renderer/gpu/compositor_dependencies.h"
 #include "content/renderer/layout_test_dependencies.h"
+#include "content/renderer/media/audio_ipc_factory.h"
 #include "gpu/ipc/client/gpu_channel_host.h"
 #include "media/media_features.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
@@ -638,6 +640,9 @@ class CONTENT_EXPORT RenderThreadImpl
   scoped_refptr<AecDumpMessageFilter> aec_dump_message_filter_;
 #endif
 
+  // Provides MojoAudioOutputIPC objects for audio output devices.
+  base::Optional<AudioIPCFactory> audio_ipc_factory_;

[o1ka, 2017/04/20 10:36:00]

unique_ptr?

Comment for it and |audio_message_filter_| than only one of those is non-null?

[Max Morin, 2017/05/05 13:10:59]

Changed to be a member.

[Max Morin, 2017/05/05 14:06:14]

Oh, actually I left it as an optional since it's not initialized in the
constructor. :)

+
   // Used on the render thread.
   std::unique_ptr<VideoCaptureImplManager> vc_manager_;