Tab Audio Capture: Browser-side connect/disconnect functionality.

content/browser/renderer_host/media/audio_renderer_host.cc

Index: content/browser/renderer_host/media/audio_renderer_host.cc
diff --git a/content/browser/renderer_host/media/audio_renderer_host.cc b/content/browser/renderer_host/media/audio_renderer_host.cc
index 83b5f2510baaa405905af5e07c561e76283b9ade..74cfb14e1a293a71b952f9a73247a4451d71854a 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.cc
+++ b/content/browser/renderer_host/media/audio_renderer_host.cc
@@ -9,6 +9,7 @@
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "content/browser/browser_main_loop.h"
+#include "content/browser/renderer_host/media/audio_mirroring_manager.h"
 #include "content/browser/renderer_host/media/audio_sync_reader.h"
 #include "content/common/media/audio_messages.h"
 #include "content/public/browser/media_observer.h"
@@ -20,16 +21,55 @@ using media::AudioBus;
 
 namespace content {
 
+namespace {
+
+// Simple wrapper around a media::AudioOutputController to implement the
+// AudioMirroringManager::Diverter interface.
+class ControllerDiverter : public AudioMirroringManager::Diverter {

[DaleCurtis, 2013/01/02 21:56:44]

ISTM that you could just have AudioOutputController implement this interface and
forgo this wrapper class.

[miu, 2013/01/03 22:30:42]

Done.

I had thought about this, but I quickly dismissed the idea because of component
boundaries (the AMM::Diverter interface is in content, whereas AOC is in media).
 However, I just tried moving the interface definition into media (i.e.,
AudioMirroringManager::Diverter is now AudioOutputStream::AudioSourceDiverter),
and it seems to work well w.r.t. code organization.

Do you like it better this way?  I could see arguments for doing things either
way.

+ public:
+  void SetController(media::AudioOutputController* controller);
+
+  // AudioMirroringManager::Diverter implementation.
+  virtual const media::AudioParameters& GetAudioParameters() OVERRIDE;
+  virtual void StartDiverting(media::AudioOutputStream* stream) OVERRIDE;
+  virtual void StopDiverting() OVERRIDE;
+
+ private:
+  media::AudioOutputController* controller_;  // Not owned.
+};

[DaleCurtis, 2013/01/02 21:56:44]

Disallow copy and assign? Why not make provide controller_ in the constructor
instead of having a SetController method?  Just make the AudioEntry version a
scoped_ptr.

[miu, 2013/01/03 22:30:42]

No longer applicable.

+
+void ControllerDiverter::SetController(media::AudioOutputController* ctlr) {
+  controller_ = ctlr;

[DaleCurtis, 2013/01/02 21:56:44]

DCHECK(ctlr) for haystack hunts.

[miu, 2013/01/03 22:30:42]

No longer applicable.

+}
+
+const media::AudioParameters& ControllerDiverter::GetAudioParameters() {
+  return controller_->params();
+}
+
+void ControllerDiverter::StartDiverting(media::AudioOutputStream* stream) {
+  controller_->StartDiverting(stream);
+}
+
+void ControllerDiverter::StopDiverting() {
+  controller_->StopDiverting();
+}
+
+}  // namespace
+
 struct AudioRendererHost::AudioEntry {
   AudioEntry();
   ~AudioEntry();
 
   // The AudioOutputController that manages the audio stream.
   scoped_refptr<media::AudioOutputController> controller;
+  ControllerDiverter diverter;
 
   // The audio stream ID.
   int stream_id;
 
+  // The routing ID of the source render view.
+  int render_view_id;
+
   // Shared memory for transmission of the audio data.
   base::SharedMemory shared_memory;
 
@@ -43,6 +83,7 @@ struct AudioRendererHost::AudioEntry {
 
 AudioRendererHost::AudioEntry::AudioEntry()
     : stream_id(0),
+      render_view_id(MSG_ROUTING_NONE),
       pending_close(false) {
 }
 
@@ -51,8 +92,13 @@ AudioRendererHost::AudioEntry::~AudioEntry() {}
 ///////////////////////////////////////////////////////////////////////////////
 // AudioRendererHost implementations.
 AudioRendererHost::AudioRendererHost(
-    media::AudioManager* audio_manager, MediaObserver* media_observer)
-    : audio_manager_(audio_manager),
+    int render_process_id,
+    media::AudioManager* audio_manager,
+    AudioMirroringManager* mirroring_manager,
+    MediaObserver* media_observer)
+    : render_process_id_(render_process_id),
+      audio_manager_(audio_manager),
+      mirroring_manager_(mirroring_manager),
       media_observer_(media_observer) {
 }
 
@@ -269,12 +315,13 @@ void AudioRendererHost::OnCreateStream(
   entry->reader.reset(reader.release());
   entry->controller = media::AudioOutputController::Create(
       audio_manager_, this, audio_params, entry->reader.get());
-
   if (!entry->controller) {
     SendErrorMessage(stream_id);
     return;
   }
 
+  entry->diverter.SetController(entry->controller);
+
   // If we have created the controller successfully, create an entry and add it
   // to the map.
   entry->stream_id = stream_id;
@@ -285,10 +332,30 @@ void AudioRendererHost::OnCreateStream(
 
 void AudioRendererHost::OnAssociateStreamWithProducer(int stream_id,
                                                       int render_view_id) {
-  // TODO(miu): Will use render_view_id in upcoming change.
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
   DVLOG(1) << "AudioRendererHost@" << this
            << "::OnAssociateStreamWithProducer(stream_id=" << stream_id
            << ", render_view_id=" << render_view_id << ")";
+
+  AudioEntry* const entry = LookupById(stream_id);
+  if (!entry) {
+    SendErrorMessage(stream_id);
+    return;
+  }
+
+  if (entry->render_view_id == render_view_id)
+    return;  // No change.
+
+  if (mirroring_manager_) {

[DaleCurtis, 2013/01/02 21:56:44]

Mirroring manager should always be present  since it's provided during the
constructor? Just DCHECK() in constructor?

[miu, 2013/01/03 22:30:42]

Done.  And fixed things so MediaObserver must never be NULL either.

+    mirroring_manager_->RemoveDiverter(
+        render_process_id_, entry->render_view_id, &entry->diverter);
+  }
+  entry->render_view_id = render_view_id;
+  if (mirroring_manager_) {
+    mirroring_manager_->AddDiverter(
+        render_process_id_, entry->render_view_id, &entry->diverter);
+  }
 }
 
 void AudioRendererHost::OnPlayStream(int stream_id) {
@@ -380,6 +447,10 @@ void AudioRendererHost::CloseAndDeleteStream(AudioEntry* entry) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   if (!entry->pending_close) {
+    if (mirroring_manager_) {

[DaleCurtis, 2013/01/02 21:56:44]

Ditto.

[miu, 2013/01/03 22:30:42]

Done.

+      mirroring_manager_->RemoveDiverter(
+          render_process_id_, entry->render_view_id, &entry->diverter);
+    }
     entry->controller->Close(
         base::Bind(&AudioRendererHost::DeleteEntry, this, entry));
     entry->pending_close = true;