[Android] A prototype of the interactive media notification.

content/browser/media/android/media_session.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_H_
 #define CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/id_map.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
+class MediaSessionBrowserTest;
+
 namespace content {
 
-class MediaSessionBrowserTest;
 class MediaSessionObserver;
 
 // MediaSession manages the Android AudioFocus for a given WebContents. It is
 // requesting the audio focus, pausing when requested by the system and dropping
 // it on demand.
 // The audio focus can be of two types: Transient or Content. A Transient audio
 // focus will allow other players to duck instead of pausing and will be
 // declared as temporary to the system. A Content audio focus will not be
 // declared as temporary and will not allow other players to duck. If a given
 // WebContents can only have one audio focus at a time, it will be Content in
 // case of Transient and Content audio focus are both requested.
 // Android system interaction occurs in the Java counterpart to this class.
 class CONTENT_EXPORT MediaSession
-    : public content::WebContentsObserver,
-      protected content::WebContentsUserData<MediaSession> {
+    : public WebContentsObserver,
+      protected WebContentsUserData<MediaSession> {
  public:
   enum class Type {
     Content,
     Transient
   };
 
   static bool RegisterMediaSession(JNIEnv* env);
 
   // Returns the MediaSession associated to this WebContents. Creates one if
   // none is currently available.
@@ skipping 15 matching lines @@
   void RemovePlayers(MediaSessionObserver* observer);
 
   // Called when the Android system requests the MediaSession to be suspended.
   // Called by Java through JNI.
   void OnSuspend(JNIEnv* env, jobject obj, jboolean temporary);
 
   // Called when the Android system requests the MediaSession to be resumed.
   // Called by Java through JNI.
   void OnResume(JNIEnv* env, jobject obj);
 
- protected:
-  friend class content::MediaSessionBrowserTest;
+  // Called when the user requests resuming the session. No-op if the session is
+  // not controllable.
+  void Resume();
+
+  // Called when the user requests suspending the session. No-op if the session
+  // is not controllable.
+  void Suspend();
+
+  // Returns if the session can be controlled by Resume() and Suspend calls
+  // above.
+  bool IsControllable() const;
+
+  // Returns if the session is currently suspended.
+  bool IsSuspended() const;
+
+ private:
+  friend class content::WebContentsUserData<MediaSession>;
+  friend class ::MediaSessionBrowserTest;
 
   // Resets the |j_media_session_| ref to prevent calling the Java backend
   // during content_browsertests.
   void ResetJavaRefForTest();
-
   bool IsActiveForTest() const;
   Type audio_focus_type_for_test() const;
+  void RemoveAllPlayersForTest();
 
-  void OnSuspend(bool temporary);
-  void OnResume();
-
- private:
-  friend class content::WebContentsUserData<MediaSession>;
+  void OnSuspendInternal(bool temporary);
+  void OnResumeInternal();
 
   enum class State {
     Active,
     TemporarilySuspended,
     Suspended,
   };
 
   // Representation of a player for the MediaSession.
   struct PlayerIdentifier {
     PlayerIdentifier(MediaSessionObserver* observer, int player_id);
@@ skipping 19 matching lines @@
 
   // Requests audio focus to Android using |j_media_session_|.
   // Returns whether the request was granted. If |j_media_session_| is null, it
   // will always return true.
   bool RequestSystemAudioFocus(Type type);
 
   // To be called after a call to AbandonAudioFocus() in order to call the Java
   // MediaSession if the audio focus really need to be abandoned.
   void AbandonSystemAudioFocusIfNeeded();
 
+  // Notifies WebContents about the state change of the media session.
+  void UpdateWebContents();
+
   base::android::ScopedJavaGlobalRef<jobject> j_media_session_;
   PlayersMap players_;
 
   State audio_focus_state_;
   Type audio_focus_type_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSession);
 };
 
 }  // namespace content
 
-#endif // CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_H_
+#endif  // CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_H_