Letting Flash join MediaSession (stack implementaion)

content/browser/media/session/media_session.cc

Index: content/browser/media/session/media_session.cc
diff --git a/content/browser/media/session/media_session.cc b/content/browser/media/session/media_session.cc
index f76c5662bfe8b284464983690958753fba80458b..89434e415b57f1474bc64e9d6af23494763cb7aa 100644
--- a/content/browser/media/session/media_session.cc
+++ b/content/browser/media/session/media_session.cc
@@ -60,6 +60,11 @@ MediaSession::~MediaSession() {
   DCHECK(audio_focus_state_ == State::INACTIVE);
 }
 
+void MediaSession::WasShown() {
+  if (IsSuspended())
+    RequestSystemAudioFocus(audio_focus_type_);
+}
+
 void MediaSession::SetMetadata(const base::Optional<MediaMetadata>& metadata) {
   metadata_ = metadata;
   // TODO(zqzhang): On Android, the metadata is sent though JNI everytime the
@@ -71,6 +76,9 @@ void MediaSession::SetMetadata(const base::Optional<MediaMetadata>& metadata) {
 bool MediaSession::AddPlayer(MediaSessionObserver* observer,
                              int player_id,
                              media::MediaContentType media_content_type) {
+  if (media_content_type == media::MediaContentType::Pepper)
+    return AddPepperPlayer(observer, player_id);
+
   observer->OnSetVolumeMultiplier(player_id, GetVolumeMultiplier());
 
   // Determine the audio focus type required for playing the new player.
@@ -122,17 +130,28 @@ void MediaSession::RemovePlayer(MediaSessionObserver* observer,
   if (it != players_.end())
     players_.erase(it);
 
+  it = pepper_players_.find(PlayerIdentifier(observer, player_id));
+  if (it != pepper_players_.end())
+    pepper_players_.erase(it);
+
   AbandonSystemAudioFocusIfNeeded();
 }
 
 void MediaSession::RemovePlayers(MediaSessionObserver* observer) {
-  for (auto it = players_.begin(); it != players_.end();) {
+  for (auto it = players_.begin(); it != players_.end(); ) {
     if (it->observer == observer)
       players_.erase(it++);
     else
       ++it;
   }
 
+  for (auto it = pepper_players_.begin(); it != pepper_players_.end(); ) {
+    if (it->observer == observer)
+      pepper_players_.erase(it++);
+    else
+      ++it;
+  }
+
   AbandonSystemAudioFocusIfNeeded();
 }
 
@@ -204,6 +223,12 @@ void MediaSession::Stop(SuspendType suspend_type) {
 
   DCHECK(audio_focus_state_ == State::SUSPENDED);
   players_.clear();
+
+  for (const auto& it : pepper_players_) {
+    it.observer->OnSetVolumeMultiplier(
+        it.player_id, GetPepperVolumeMultiplier());
+  }
+
   AbandonSystemAudioFocusIfNeeded();
 }
 
@@ -230,6 +255,14 @@ double MediaSession::GetVolumeMultiplier() const {
   return is_ducking_ ? kDuckingVolumeMultiplier : kDefaultVolumeMultiplier;
 }
 
+double MediaSession::GetPepperVolumeMultiplier() const {
+  if (is_ducking_)
+    return kDuckingVolumeMultiplier;
+  if (!IsActive() && !allow_pepper_override_ducking_)
+    return kDuckingVolumeMultiplier;
+  return kDefaultVolumeMultiplier;
+}
+
 bool MediaSession::IsActive() const {
   return audio_focus_state_ == State::ACTIVE;
 }
@@ -250,6 +283,10 @@ bool MediaSession::IsControllable() const {
          audio_focus_type_ == AudioFocusManager::AudioFocusType::Gain;
 }
 
+bool MediaSession::HasPepper() const {
+  return !pepper_players_.empty();
+}
+
 std::unique_ptr<base::CallbackList<void(MediaSession::State)>::Subscription>
 MediaSession::RegisterMediaSessionStateChangedCallbackForTest(
     const StateChangedCallback& cb) {
@@ -323,6 +360,9 @@ void MediaSession::OnSuspendInternal(SuspendType suspend_type,
       it.observer->OnSuspend(it.player_id);
   }
 
+  for (const auto& it : pepper_players_)
+    it.observer->OnSetVolumeMultiplier(it.player_id, kDuckingVolumeMultiplier);
+
   UpdateWebContents();
 }
 
@@ -335,6 +375,10 @@ void MediaSession::OnResumeInternal(SuspendType suspend_type) {
   for (const auto& it : players_)
     it.observer->OnResume(it.player_id);
 
+  for (const auto& it : pepper_players_)
+    it.observer->OnSetVolumeMultiplier(
+        it.player_id, GetPepperVolumeMultiplier());
+
   UpdateWebContents();
 }
 
@@ -343,7 +387,8 @@ MediaSession::MediaSession(WebContents* web_contents)
       audio_focus_state_(State::INACTIVE),
       audio_focus_type_(
           AudioFocusManager::AudioFocusType::GainTransientMayDuck),
-      is_ducking_(false) {}
+      is_ducking_(false),
+      allow_pepper_override_ducking_(false) {}
 
 void MediaSession::Initialize() {
   delegate_ = MediaSessionDelegate::Create(this);
@@ -357,7 +402,8 @@ bool MediaSession::RequestSystemAudioFocus(
 }
 
 void MediaSession::AbandonSystemAudioFocusIfNeeded() {
-  if (audio_focus_state_ == State::INACTIVE || !players_.empty())
+  if (audio_focus_state_ == State::INACTIVE || !players_.empty() ||
+      !pepper_players_.empty())
     return;
 
   delegate_->AbandonAudioFocus();
@@ -389,4 +435,41 @@ void MediaSession::SetAudioFocusState(State audio_focus_state) {
   }
 }
 
+bool MediaSession::AddPepperPlayer(MediaSessionObserver* observer,
+                                   int player_id) {
+  AudioFocusManager::AudioFocusType focus_type =
+      AudioFocusManager::AudioFocusType::Gain;
+  State audio_focus_state =
+      RequestSystemAudioFocus(focus_type) ? State::ACTIVE : State::INACTIVE;
+  SetAudioFocusState(audio_focus_state);
+  audio_focus_type_ = focus_type;
+  pepper_players_.insert(PlayerIdentifier(observer, player_id));
+
+  observer->OnSetVolumeMultiplier(player_id, GetPepperVolumeMultiplier());
+
+  return true;
+}
+
+void MediaSession::AllowPepperOverrideDucking() {

[whywhat, 2016/09/13 00:16:17]

nit: clear candidate to unification as AllowDisallowPepperOverrideDucking() :)
These two methods are twins.

[Zhiqiang Zhang (Slow), 2016/09/22 12:30:33]

This method is removed since there's no longer complex Pepper-specific ducking
logic in this CL.

+  if (allow_pepper_override_ducking_)
+    return;
+
+  allow_pepper_override_ducking_ = true;
+  for (const auto& it : pepper_players_) {
+    it.observer->OnSetVolumeMultiplier(
+        it.player_id, GetPepperVolumeMultiplier());
+  }
+}
+
+void MediaSession::DisallowPepperOverrideDucking() {
+  if (!allow_pepper_override_ducking_)
+    return;
+
+  allow_pepper_override_ducking_ = false;
+  for (const auto& it : pepper_players_) {
+    it.observer->OnSetVolumeMultiplier(
+        it.player_id, GetPepperVolumeMultiplier());
+  }
+}
+
 }  // namespace content