Add new setScreenshareActive key to media-session (#2710)

Author: ddbeck

features/media-session.yml

@@ -35,5 +35,6 @@ compat_features:
   - api.MediaSession.setActionHandler.togglemicrophone_type
   - api.MediaSession.setCameraActive
   - api.MediaSession.setMicrophoneActive
+  - api.MediaSession.setScreenshareActive
   - api.MediaSession.setPositionState
   - api.Navigator.mediaSession

features/media-session.yml.dist

@@ -128,3 +128,7 @@ compat_features:
   - api.ChapterInformation.startTime
   - api.ChapterInformation.title
   - api.MediaMetadata.chapterInfo
+
+  # baseline: false
+  # support: {}
+  - api.MediaSession.setScreenshareActive