Unmute Tab Audio For Desktop Share

content/browser/media/capture/web_contents_audio_input_stream.cc

Index: content/browser/media/capture/web_contents_audio_input_stream.cc
diff --git a/content/browser/media/capture/web_contents_audio_input_stream.cc b/content/browser/media/capture/web_contents_audio_input_stream.cc
index ce8f7f46419f158a31a0540eb0b9583e997d0848..a345a37dc7bcaecb4685ed97f8b0f3d80684f76a 100644
--- a/content/browser/media/capture/web_contents_audio_input_stream.cc
+++ b/content/browser/media/capture/web_contents_audio_input_stream.cc
@@ -29,10 +29,12 @@ class WebContentsAudioInputStream::Impl
       public AudioMirroringManager::MirroringDestination {
  public:
   // Takes ownership of |mixer_stream|.  The rest outlive this instance.
-  Impl(int render_process_id, int main_render_frame_id,
+  Impl(int render_process_id,
+       int main_render_frame_id,
        AudioMirroringManager* mirroring_manager,
        const scoped_refptr<WebContentsTracker>& tracker,
-       media::VirtualAudioInputStream* mixer_stream);
+       media::VirtualAudioInputStream* mixer_stream,
+       bool is_duplication);
 
   // Open underlying VirtualAudioInputStream and start tracker.
   bool Open();
@@ -86,9 +88,12 @@ class WebContentsAudioInputStream::Impl
                                  const MatchesCallback& results_callback);
   media::AudioOutputStream* AddInput(
       const media::AudioParameters& params) override;
+  media::AudioPushSink* AddPushInput(
+      const media::AudioParameters& params) override;
 
   // Callback which is run when |stream| is closed.  Deletes |stream|.
   void ReleaseInput(media::VirtualAudioOutputStream* stream);
+  void ReleasePushInput(media::VirtualAudioSink* sink);
 
   // Called by WebContentsTracker when the target of the audio mirroring has
   // changed.
@@ -112,16 +117,22 @@ class WebContentsAudioInputStream::Impl
   // Current callback used to consume the resulting mixed audio data.
   AudioInputCallback* callback_;
 
+  // If true, this WebContentsAudioInputStream will request a duplication of
+  // audio data.

[miu, 2016/05/06 22:29:49]

nit: Append to the end of the sentence: "instead of exclusive access to pull the
audio data."

[qiangchen, 2016/05/10 22:36:52]

Done.

+  bool is_duplication_;
+
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(Impl);
 };
 
 WebContentsAudioInputStream::Impl::Impl(
-    int render_process_id, int main_render_frame_id,
+    int render_process_id,
+    int main_render_frame_id,
     AudioMirroringManager* mirroring_manager,
     const scoped_refptr<WebContentsTracker>& tracker,
-    media::VirtualAudioInputStream* mixer_stream)
+    media::VirtualAudioInputStream* mixer_stream,
+    bool is_duplication)
     : initial_render_process_id_(render_process_id),
       initial_main_render_frame_id_(main_render_frame_id),
       mirroring_manager_(mirroring_manager),
@@ -129,7 +140,8 @@ WebContentsAudioInputStream::Impl::Impl(
       mixer_stream_(mixer_stream),
       state_(CONSTRUCTED),
       is_target_lost_(false),
-      callback_(NULL) {
+      callback_(NULL),
+      is_duplication_(is_duplication) {
   DCHECK(mirroring_manager_);
   DCHECK(tracker_);
   DCHECK(mixer_stream_);
@@ -283,7 +295,7 @@ void WebContentsAudioInputStream::Impl::QueryForMatchesOnUIThread(
     }
   }
 
-  results_callback.Run(matches);
+  results_callback.Run(matches, is_duplication_);
 }
 
 media::AudioOutputStream* WebContentsAudioInputStream::Impl::AddInput(
@@ -302,6 +314,20 @@ void WebContentsAudioInputStream::Impl::ReleaseInput(
   delete stream;
 }
 
+media::AudioPushSink* WebContentsAudioInputStream::Impl::AddPushInput(
+    const media::AudioParameters& params) {
+  // Note: The closure created here holds a reference to "this," which will
+  // guarantee the VirtualAudioInputStream (mixer_stream_) outlives the
+  // VirtualAudioSink.
+  return new media::VirtualAudioSink(params, mixer_stream_.get(),
+                                     base::Bind(&Impl::ReleasePushInput, this));
+}
+
+void WebContentsAudioInputStream::Impl::ReleasePushInput(
+    media::VirtualAudioSink* stream) {
+  delete stream;
+}
+
 void WebContentsAudioInputStream::Impl::OnTargetChanged(bool had_target) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
@@ -330,22 +356,29 @@ WebContentsAudioInputStream* WebContentsAudioInputStream::Create(
     return NULL;
   }
 
+  // TODO(qiangchen): Plug in true for the case of Tab Typed Desktop Share.

[miu, 2016/05/06 22:29:49]

Note: The JavaScript API to start tab capture should specify whether it wants
the local audio diverted or duplicated. For historical reasons, if the
"constraint" or "parameter" for this is not specified, it should probably
default to "diverted."

[qiangchen, 2016/05/10 22:36:52]

For the current use case: Cast uses chrome.tabCapture, while hangouts uses
chrome.chooseDesktopMedia.
So we can set the duplication=true/false based on which API issues the request,
without touching API.

Your suggestion sounds more reasonable. I'll consider adding an entry in
AudioConstraint for the API call, so that we do not need to change the signature
of API.

   return new WebContentsAudioInputStream(
-      render_process_id, main_render_frame_id,
-      audio_mirroring_manager,
+      render_process_id, main_render_frame_id, audio_mirroring_manager,
       new WebContentsTracker(false),
       new media::VirtualAudioInputStream(
           params, worker_task_runner,
-          media::VirtualAudioInputStream::AfterCloseCallback()));
+          media::VirtualAudioInputStream::AfterCloseCallback()),
+      false);
 }
 
 WebContentsAudioInputStream::WebContentsAudioInputStream(
-    int render_process_id, int main_render_frame_id,
+    int render_process_id,
+    int main_render_frame_id,
     AudioMirroringManager* mirroring_manager,
     const scoped_refptr<WebContentsTracker>& tracker,
-    media::VirtualAudioInputStream* mixer_stream)
-    : impl_(new Impl(render_process_id, main_render_frame_id,
-                     mirroring_manager, tracker, mixer_stream)) {}
+    media::VirtualAudioInputStream* mixer_stream,
+    bool is_duplication)
+    : impl_(new Impl(render_process_id,
+                     main_render_frame_id,
+                     mirroring_manager,
+                     tracker,
+                     mixer_stream,
+                     is_duplication)) {}
 
 WebContentsAudioInputStream::~WebContentsAudioInputStream() {}