Added initial set of logging for AudioOutputController.

content/browser/renderer_host/media/audio_output_delegate_impl.cc

Index: content/browser/renderer_host/media/audio_output_delegate_impl.cc
diff --git a/content/browser/renderer_host/media/audio_output_delegate_impl.cc b/content/browser/renderer_host/media/audio_output_delegate_impl.cc
index 3625fcbfefaaa18f1dabe65e3af7eabbc3175f99..2d41e509a44701e338f21ca1bb0dbf183fec953f 100644
--- a/content/browser/renderer_host/media/audio_output_delegate_impl.cc
+++ b/content/browser/renderer_host/media/audio_output_delegate_impl.cc
@@ -12,6 +12,7 @@
 #include "content/browser/media/capture/audio_mirroring_manager.h"
 #include "content/browser/media/media_internals.h"
 #include "content/browser/renderer_host/media/audio_sync_reader.h"
+#include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/media_observer.h"
 #include "media/audio/audio_output_controller.h"
@@ -25,21 +26,24 @@ namespace content {
 class AudioOutputDelegateImpl::ControllerEventHandler
     : public media::AudioOutputController::EventHandler {
  public:
-  explicit ControllerEventHandler(
-      base::WeakPtr<AudioOutputDelegateImpl> delegate);
+  ControllerEventHandler(base::WeakPtr<AudioOutputDelegateImpl> delegate,
+                         int stream_id);
 
  private:
   void OnControllerCreated() override;
   void OnControllerPlaying() override;
   void OnControllerPaused() override;
   void OnControllerError() override;
+  void OnLog(const std::string& message) override;
 
   base::WeakPtr<AudioOutputDelegateImpl> delegate_;
+  const int stream_id_;  // Retained separately for logging.
 };
 
 AudioOutputDelegateImpl::ControllerEventHandler::ControllerEventHandler(
-    base::WeakPtr<AudioOutputDelegateImpl> delegate)
-    : delegate_(std::move(delegate)) {}
+    base::WeakPtr<AudioOutputDelegateImpl> delegate,
+    int stream_id)
+    : delegate_(std::move(delegate)), stream_id_(stream_id) {}
 
 void AudioOutputDelegateImpl::ControllerEventHandler::OnControllerCreated() {
   BrowserThread::PostTask(
@@ -68,6 +72,15 @@ void AudioOutputDelegateImpl::ControllerEventHandler::OnControllerError() {
       base::BindOnce(&AudioOutputDelegateImpl::OnError, delegate_));
 }
 
+void AudioOutputDelegateImpl::ControllerEventHandler::OnLog(
+    const std::string& message) {
+  std::ostringstream oss;
+  oss << "[stream_id=" << stream_id_ << "] " << message;
+  const std::string out_message = oss.str();
+  content::MediaStreamManager::SendMessageToNativeLog(out_message);
+  DVLOG(1) << out_message;
+}
+
 std::unique_ptr<media::AudioOutputDelegate> AudioOutputDelegateImpl::Create(
     EventHandler* handler,
     media::AudioManager* audio_manager,
@@ -118,8 +131,8 @@ AudioOutputDelegateImpl::AudioOutputDelegateImpl(
   // Since the event handler never directly calls functions on |this| but rather
   // posts them to the IO thread, passing a pointer from the constructor is
   // safe.
-  controller_event_handler_ =
-      base::MakeUnique<ControllerEventHandler>(weak_factory_.GetWeakPtr());
+  controller_event_handler_ = base::MakeUnique<ControllerEventHandler>(
+      weak_factory_.GetWeakPtr(), stream_id_);
   audio_log_->OnCreated(stream_id, params, output_device_id);
   controller_ = media::AudioOutputController::Create(
       audio_manager, controller_event_handler_.get(), params, output_device_id,