Implement MediaSession on top of the WebMediaPlayerDelegate.

content/browser/media/android/media_web_contents_observer_android.cc

Index: content/browser/media/android/media_web_contents_observer_android.cc
diff --git a/content/browser/media/android/media_web_contents_observer_android.cc b/content/browser/media/android/media_web_contents_observer_android.cc
index 1b48959e9bad9ae15030a60b37bcce87c4d49bd8..aa66741fd92fe0de407e3498f4281d59a11fecfc 100644
--- a/content/browser/media/android/media_web_contents_observer_android.cc
+++ b/content/browser/media/android/media_web_contents_observer_android.cc
@@ -6,9 +6,11 @@
 
 #include "content/browser/media/android/browser_media_player_manager.h"
 #include "content/browser/media/android/browser_media_session_manager.h"
+#include "content/browser/media/android/media_session.h"
 #include "content/browser/media/android/media_session_observer.h"
 #include "content/browser/media/cdm/browser_cdm_manager.h"
 #include "content/browser/web_contents/web_contents_impl.h"
+#include "content/common/frame_messages.h"
 #include "content/common/media/media_player_messages_android.h"
 #include "content/common/media/media_session_messages_android.h"
 #include "content/public/browser/render_frame_host.h"
@@ -18,6 +20,80 @@
 
 namespace content {
 
+class MediaSessionController : public MediaSessionObserver {
+ public:
+  MediaSessionController(const WebContentsObserver::MediaPlayerId& id,
+                         MediaWebContentsObserver* media_web_contents_observer)
+      : id_(id), media_web_contents_observer_(media_web_contents_observer) {}
+
+  // Clients must call this after construction and destroy the controller if it
+  // returns false.
+  bool Initialize(bool has_audio, bool is_remote, base::TimeDelta duration) {
+    // These objects are only created on the UI thread, so this is safe.
+    static uint32_t player_id = 0;
+    player_id_ = static_cast<int>(player_id++);
+
+    // Don't bother with a MediaSession for remote players or without audio.
+    if (!has_audio || is_remote)
+      return true;
+
+    // Minimal duration of a player in order to be considered as Content type.
+    const base::TimeDelta kMinimumDurationForContent =
+        base::TimeDelta::FromSeconds(5);
+
+    const MediaSession::Type media_session_type =
+        duration == base::TimeDelta() || duration > kMinimumDurationForContent
+            ? MediaSession::Type::Content
+            : MediaSession::Type::Transient;
+
+    // If a session can't be created, force a pause immediately.
+    if (!MediaSession::Get(media_web_contents_observer_->web_contents())
+             ->AddPlayer(this, player_id_, media_session_type)) {
+      OnSuspend(player_id_);
+      return false;
+    }
+
+    initialized_ = true;
+    return true;
+  }
+
+  ~MediaSessionController() {
+    if (initialized_) {
+      MediaSession::Get(media_web_contents_observer_->web_contents())
+          ->RemovePlayer(this, player_id_);
+    }
+  }
+
+  void OnSuspend(int player_id) {
+    DCHECK_EQ(player_id_, player_id);
+    media_web_contents_observer_->Send(
+        new FrameMsg_MediaDelegatePause(id_.first->GetRoutingID(), id_.second));
+  }
+
+  void OnResume(int player_id) {
+    DCHECK_EQ(player_id_, player_id);
+    media_web_contents_observer_->Send(
+        new FrameMsg_MediaDelegatePlay(id_.first->GetRoutingID(), id_.second));
+  }
+
+  void PausePlayback() {
+    MediaSession* session =
+        MediaSession::Get(media_web_contents_observer_->web_contents());
+    // We check for suspension here since the renderer may issue its own pause
+    // in response to or while a pause from the browser is in flight.
+    if (!session->IsSuspended())
+      session->OnPlayerPaused(this, player_id_);
+  }
+
+ private:
+  const WebContentsObserver::MediaPlayerId id_;
+  MediaWebContentsObserver* const media_web_contents_observer_;
+  int player_id_ = 0;
+  bool initialized_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaSessionController);
+};
+
 MediaWebContentsObserverAndroid::MediaWebContentsObserverAndroid(
     WebContents* web_contents)
     : MediaWebContentsObserver(web_contents) {}
@@ -58,6 +134,19 @@ MediaWebContentsObserverAndroid::GetMediaSessionManager(
   return manager;
 }
 
+bool MediaWebContentsObserverAndroid::RequestPlay(
+    RenderFrameHost* render_frame_host,
+    int64_t player_cookie,
+    bool has_audio,
+    bool is_remote,
+    base::TimeDelta duration) {
+  // |has_video| forced to true since the value doesn't matter at present.
+  OnMediaPlayingNotification(render_frame_host, player_cookie, true,
+                             has_audio, is_remote, duration);
+  return media_session_map_.find(MediaPlayerId(
+             render_frame_host, player_cookie)) != media_session_map_.end();
+}
+
 #if defined(VIDEO_HOLE)
 void MediaWebContentsObserverAndroid::OnFrameInfoUpdated() {
   for (auto it = media_player_managers_.begin();
@@ -71,6 +160,13 @@ void MediaWebContentsObserverAndroid::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
   MediaWebContentsObserver::RenderFrameDeleted(render_frame_host);
 
+  for (auto it = media_session_map_.begin(); it != media_session_map_.end();) {
+    if (it->first.first == render_frame_host)
+      it = media_session_map_.erase(it);
+    else
+      ++it;
+  }
+
   // Always destroy the media players before CDMs because we do not support
   // detaching CDMs from media players yet. See http://crbug.com/330324
   media_player_managers_.erase(render_frame_host);
@@ -90,6 +186,10 @@ void MediaWebContentsObserverAndroid::RenderFrameDeleted(
 bool MediaWebContentsObserverAndroid::OnMessageReceived(
     const IPC::Message& msg,
     RenderFrameHost* render_frame_host) {
+  // Receive play/pause/destroyed messages, but don't mark as processed so they
+  // are also handled by MediaWebContentsObserver.
+  OnMediaPlayerDelegateMessageReceived(msg, render_frame_host);
+
   if (MediaWebContentsObserver::OnMessageReceived(msg, render_frame_host))
     return true;
 
@@ -99,6 +199,21 @@ bool MediaWebContentsObserverAndroid::OnMessageReceived(
   return OnMediaPlayerSetCdmMessageReceived(msg, render_frame_host);
 }
 
+void MediaWebContentsObserverAndroid::OnMediaPlayerDelegateMessageReceived(
+    const IPC::Message& msg,
+    RenderFrameHost* render_frame_host) {
+  // TODO(dalecurtis): These should no longer be FrameHostMsg.
+  IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(MediaWebContentsObserverAndroid, msg,
+                                   render_frame_host)
+    IPC_MESSAGE_HANDLER(FrameHostMsg_MediaDestroyedNotification,
+                        OnMediaDestroyedNotification)
+    IPC_MESSAGE_HANDLER(FrameHostMsg_MediaPlayingNotification,
+                        OnMediaPlayingNotification)
+    IPC_MESSAGE_HANDLER(FrameHostMsg_MediaPausedNotification,
+                        OnMediaPausedNotification)
+  IPC_END_MESSAGE_MAP()
+}
+
 bool MediaWebContentsObserverAndroid::OnMediaPlayerMessageReceived(
     const IPC::Message& msg,
     RenderFrameHost* render_frame_host) {
@@ -197,4 +312,51 @@ void MediaWebContentsObserverAndroid::OnSetCdm(
   media_player->SetCdm(cdm);
 }
 
+void MediaWebContentsObserverAndroid::OnMediaDestroyedNotification(
+    RenderFrameHost* render_frame_host,
+    int64_t player_cookie) {
+  media_session_map_.erase(MediaPlayerId(render_frame_host, player_cookie));
+}
+
+void MediaWebContentsObserverAndroid::OnMediaPlayingNotification(
+    RenderFrameHost* render_frame_host,
+    int64_t player_cookie,
+    bool has_video,
+    bool has_audio,
+    bool is_remote,
+    base::TimeDelta duration) {
+  // TODO(dalecurtis): Remove this allowance once RequestPlay() is deleted.
+  const MediaPlayerId id(render_frame_host, player_cookie);
+  if (media_session_map_.find(id) != media_session_map_.end())
+    return;
+
+  scoped_ptr<MediaSessionController> controller(
+      new MediaSessionController(id, this));
+
+  // If initialize fails, the controller should be destroyed and a new one
+  // attempted later after another playback attempt occurs.
+  if (!controller->Initialize(has_audio, is_remote, duration))
+    return;
+
+  media_session_map_[id] = std::move(controller);
+}
+
+void MediaWebContentsObserverAndroid::OnMediaPausedNotification(
+    RenderFrameHost* render_frame_host,
+    int64_t player_cookie,
+    bool reached_end_of_stream) {
+  // Drop the session if playback completes normally.
+  if (reached_end_of_stream) {
+    OnMediaDestroyedNotification(render_frame_host, player_cookie);
+    return;
+  }
+
+  auto it =
+      media_session_map_.find(MediaPlayerId(render_frame_host, player_cookie));
+  if (it == media_session_map_.end())
+    return;
+
+  it->second->PausePlayback();
+}
+
 }  // namespace content