Make MediaSession a runtime-enabled feature on Desktop.

content/browser/media/session/media_session.h

Index: content/browser/media/session/media_session.h
diff --git a/content/browser/media/android/media_session.h b/content/browser/media/session/media_session.h
similarity index 65%
rename from content/browser/media/android/media_session.h
rename to content/browser/media/session/media_session.h
index 12711245bfbf4bdc3c70d347f6f1ef5fdae5df8e..f67af113d1a9d077b73a1d4a2886f3cc6d23a162 100644
--- a/content/browser/media/android/media_session.h
+++ b/content/browser/media/session/media_session.h
@@ -2,16 +2,14 @@
 // 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_
+#ifndef CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_H_
+#define CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_H_
 
-#include <jni.h>
 #include <stddef.h>
 
-#include "base/android/scoped_java_ref.h"
 #include "base/id_map.h"
 #include "base/macros.h"
-#include "content/browser/media/android/media_session_uma_helper.h"
+#include "content/browser/media/session/media_session_uma_helper.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
@@ -20,18 +18,18 @@ class MediaSessionBrowserTest;
 
 namespace content {
 
+class MediaSessionDelegate;
 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.
+// MediaSession manages the media session and audio focus 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 WebContentsObserver,
       protected WebContentsUserData<MediaSession> {
@@ -41,7 +39,15 @@ class CONTENT_EXPORT MediaSession
     Transient
   };
 
-  static bool RegisterMediaSession(JNIEnv* env);
+  enum class SuspendType {
+    // Suspended by the system because a transient sound needs to be played.
+    SYSTEM,
+    // Suspended by the UI.
+    UI,
+    // Suspended by the page via script or user interaction.
+    CONTENT,
+  };
+
 
   // Returns the MediaSession associated to this WebContents. Creates one if
   // none is currently available.
@@ -62,56 +68,50 @@ class CONTENT_EXPORT MediaSession
   // these were the last players in the session.
   void RemovePlayers(MediaSessionObserver* observer);
 
-  // Called when the Android system requests the MediaSession to be suspended.
-  // Called by Java through JNI.
-  void OnSuspend(JNIEnv* env,
-                 const base::android::JavaParamRef<jobject>& obj,
-                 jboolean temporary);
-
-  // Called when the Android system requests the MediaSession to duck.
-  // Called by Java through JNI.
-  void OnSetVolumeMultiplier(JNIEnv* env, jobject obj,
-                             jdouble volume_multiplier);
-
-  // Called when the Android system requests the MediaSession to be resumed.
-  // Called by Java through JNI.
-  void OnResume(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
-
-  // Called when the Android system requests the MediaSession to duck.
-  // Called by Java through JNI.
-  void RecordSessionDuck(JNIEnv* env,
-                         const base::android::JavaParamRef<jobject> &obj);
+  // Record that the session was ducked.
+  void RecordSessionDuck();
 
   // Called when a player is paused in the content.
   // If the paused player is the last player, we suspend the MediaSession.
   // Otherwise, the paused player will be removed from the MediaSession.
   void OnPlayerPaused(MediaSessionObserver* observer, int player_id);
 
-  // Called when the user requests resuming the session. No-op if the session is
-  // not controllable.
-  void Resume();
+  // Resume the media session.
+  // |type| represents the origin of the request.
+  void Resume(SuspendType type);
 
-  // Called when the user requests suspending the session. No-op if the session
-  // is not controllable.
-  void Suspend();
+  // Suspend the media session.
+  // |type| represents the origin of the request.
+  void Suspend(SuspendType type);
 
-  // Called when the user requests stopping the session.
-  void Stop();
+  // Stop the media session.
+  // |type| represents the origin of the request.
+  void Stop(SuspendType type);
+
+  // Change the volume multiplier of the session to |volume_multiplier|.
+  void SetVolumeMultiplier(double volume_multiplier);
 
   // Returns if the session can be controlled by Resume() and Suspend calls
   // above.
   bool IsControllable() const;
 
+  // Returns if the session is currently active.
+  bool IsActive() const;
+
   // Returns if the session is currently suspended.
+  // TODO(mlamouri): IsSuspended() is basically !IsActive() but in order to not
+  // have a ridiculously huge refactoring, the change to fix that will happen in
+  // a follow-up.
+  bool IsReallySuspended() const;
+
+  // Returns if the session is currently suspended or inactive.
   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();
+  void SetDelegateForTest(scoped_ptr<MediaSessionDelegate> delegate);
   bool IsActiveForTest() const;
   Type audio_focus_type_for_test() const;
   void RemoveAllPlayersForTest();
@@ -123,15 +123,6 @@ class CONTENT_EXPORT MediaSession
     INACTIVE
   };
 
-  enum class SuspendType {
-    // Suspended by the system because a transient sound needs to be played.
-    SYSTEM,
-    // Suspended by the UI.
-    UI,
-    // Suspended by the page via script or user interaction.
-    CONTENT,
-  };
-
   // Representation of a player for the MediaSession.
   struct PlayerIdentifier {
     PlayerIdentifier(MediaSessionObserver* observer, int player_id);
@@ -152,20 +143,17 @@ class CONTENT_EXPORT MediaSession
 
   explicit MediaSession(WebContents* web_contents);
 
-  // Setup the JNI.
   void Initialize();
 
   void OnSuspendInternal(SuspendType type, State new_state);
   void OnResumeInternal(SuspendType type);
-  void OnSetVolumeMultiplierInternal(double volume_multiplier);
 
-  // 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.
+  // Requests audio focus to the MediaSessionDelegate.
+  // Returns whether the request was granted.
   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.
+  // To be called after a call to AbandonAudioFocus() in order request the
+  // delegate to abandon the audio focus.
   void AbandonSystemAudioFocusIfNeeded();
 
   // Notifies WebContents about the state change of the media session.
@@ -175,7 +163,7 @@ class CONTENT_EXPORT MediaSession
   // It sets audio_focus_state_ and notifies observers about the state change.
   void SetAudioFocusState(State audio_focus_state);
 
-  base::android::ScopedJavaGlobalRef<jobject> j_media_session_;
+  scoped_ptr<MediaSessionDelegate> delegate_;
   PlayersMap players_;
 
   State audio_focus_state_;
@@ -193,4 +181,4 @@ class CONTENT_EXPORT MediaSession
 
 }  // namespace content
 
-#endif  // CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_SESSION_H_
+#endif  // CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_H_