[Media Controller] Add SuspendAllSessions

Add SuspendAllSessions mojo API to suspend all
media sessions. This will be used to pause
playback when the audio output is detached.

BUG=905923

Change-Id: I540ef1a78ec6f9e8d7eec0b4cb39f783db58e641
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1568831Reviewed-by: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#651745}

services/media_session/audio_focus_manager.cc

@@ -376,6 +376,11 @@ void AudioFocusManager::CreateMediaControllerForSession(
   }
 }
 
+void AudioFocusManager::SuspendAllSessions() {
+  for (auto& row : audio_focus_stack_)
+    row->session()->Suspend(mojom::MediaSession::SuspendType::kUI);
+}
+
 void AudioFocusManager::BindToInterface(
     mojom::AudioFocusManagerRequest request) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

services/media_session/audio_focus_manager.h

@@ -67,6 +67,7 @@ class AudioFocusManager : public mojom::AudioFocusManager,
   void CreateMediaControllerForSession(
       mojom::MediaControllerRequest request,
       const base::UnguessableToken& request_id) override;
+  void SuspendAllSessions() override;
 
   // Bind to a mojom::AudioFocusManagerRequest.
   void BindToInterface(mojom::AudioFocusManagerRequest request);

services/media_session/media_controller_unittest.cc

@@ -1158,4 +1158,34 @@ TEST_F(MediaControllerTest, BoundController_Observer_SessionChanged) {
   }
 }
 
+TEST_F(MediaControllerTest, Manager_SuspendAllSessions) {
+  test::MockMediaSession media_session_1;
+  test::MockMediaSession media_session_2;
+
+  {
+    test::MockMediaSessionMojoObserver observer(media_session_1);
+    RequestAudioFocus(media_session_1, mojom::AudioFocusType::kGain);
+    observer.WaitForPlaybackState(mojom::MediaPlaybackState::kPlaying);
+  }
+
+  {
+    test::MockMediaSessionMojoObserver observer(media_session_2);
+    RequestAudioFocus(media_session_2,
+                      mojom::AudioFocusType::kGainTransientMayDuck);
+    observer.WaitForPlaybackState(mojom::MediaPlaybackState::kPlaying);
+  }
+
+  manager()->SuspendAllSessions();
+
+  {
+    test::MockMediaSessionMojoObserver observer(media_session_1);
+    observer.WaitForPlaybackState(mojom::MediaPlaybackState::kPaused);
+  }
+
+  {
+    test::MockMediaSessionMojoObserver observer(media_session_2);
+    observer.WaitForPlaybackState(mojom::MediaPlaybackState::kPaused);
+  }
+}
+
 }  // namespace media_session

services/media_session/public/mojom/media_controller.mojom

@@ -19,6 +19,9 @@ interface MediaControllerManager {
   // automatically route commands to the correct session if the active session
   // changes. If there is no active session then commands will be no-ops.
   CreateActiveMediaController(MediaController& request);
+
+  // Suspends all media sessions.
+  SuspendAllSessions();
 };
 
 // Controls a MediaSession. If the media session is not controllable then the