NOT FOR LANDING Implement WebMediaSession

content/browser/media/android/media_session.cc

Index: content/browser/media/android/media_session.cc
diff --git a/content/browser/media/android/media_session.cc b/content/browser/media/android/media_session.cc
index a32159679fa0711ca3c059b47a1b5a190683ff87..c9eab552a91a706f8d8d2aae2fe81f44c902370a 100644
--- a/content/browser/media/android/media_session.cc
+++ b/content/browser/media/android/media_session.cc
@@ -54,11 +54,38 @@ MediaSession* MediaSession::Get(WebContents* web_contents) {
   return session;
 }
 
+// static
+MediaSession* MediaSession::Create(WebContents* web_contents, int session_id) {
+  MediaSession* session = new MediaSession(web_contents, session_id);
+  session->Initialize();
+  return session;
+}
+
 MediaSession::~MediaSession() {
   DCHECK(players_.empty());
   DCHECK(audio_focus_state_ == State::INACTIVE);
 }
 
+bool MediaSession::Activate() {
+  if (audio_focus_state_ == State::ACTIVE)
+    return true;
+
+  const Type type = Type::Content;
+  if (!RequestSystemAudioFocus(type))
+    return false;
+
+  audio_focus_state_ = State::ACTIVE;
+  audio_focus_type_ = type;
+  UpdateWebContents();
+
+  return true;
+}
+
+void MediaSession::Deactivate() {
+  AbandonSystemAudioFocusIfNeeded();
+  DCHECK(audio_focus_state_ == State::INACTIVE);
+}
+
 bool MediaSession::AddPlayer(MediaSessionObserver* observer,
                              int player_id,
                              Type type) {
@@ -267,10 +294,11 @@ void MediaSession::OnResumeInternal(SuspendType type) {
   UpdateWebContents();
 }
 
-MediaSession::MediaSession(WebContents* web_contents)
+MediaSession::MediaSession(WebContents* web_contents, int session_id_)
     : WebContentsObserver(web_contents),
       audio_focus_state_(State::INACTIVE),
-      audio_focus_type_(Type::Transient) {}
+      audio_focus_type_(Type::Transient),
+      session_id_(session_id_) {}
 
 void MediaSession::Initialize() {
   JNIEnv* env = base::android::AttachCurrentThread();
@@ -310,7 +338,8 @@ void MediaSession::AbandonSystemAudioFocusIfNeeded() {
 }
 
 void MediaSession::UpdateWebContents() {
-  static_cast<WebContentsImpl*>(web_contents())->OnMediaSessionStateChanged();
+  static_cast<WebContentsImpl*>(web_contents())
+      ->OnMediaSessionStateChanged(this);
 }
 
 void MediaSession::SetAudioFocusState(State audio_focus_state) {