[MediaSession] Add playbackState attribute to Blink MediaSession and use it to determine playback s…

chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java b/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
index d8a6e6a8bf19d545a76a1b594eb47b0a51d34d6e..8a95b7cefef995982126c04a7fca18aac0b23c31 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaNotificationManager.java
@@ -885,7 +885,6 @@ public class MediaNotificationManager {
         // https://crbug.com/667500
         if (mMediaNotificationInfo.supportsPlayPause()) {
             actions.addAll(mMediaNotificationInfo.mediaSessionActions);
-            actions.remove(MediaSessionAction.PLAY_PAUSE);
             if (mMediaNotificationInfo.isPaused) {
                 actions.remove(MediaSessionAction.PAUSE);
                 actions.add(MediaSessionAction.PLAY);
@@ -970,8 +969,6 @@ public class MediaNotificationManager {
         assert !actions.contains(MediaSessionAction.PLAY)
                 || !actions.contains(MediaSessionAction.PAUSE);
 
-        assert !actions.contains(MediaSessionAction.PLAY_PAUSE);
-
         int[] actionByOrder = {
                 MediaSessionAction.PREVIOUS_TRACK,
                 MediaSessionAction.SEEK_BACKWARD,
@@ -1036,8 +1033,6 @@ public class MediaNotificationManager {
         assert !actions.contains(MediaSessionAction.PLAY)
                 || !actions.contains(MediaSessionAction.PAUSE);
 
-        assert !actions.contains(MediaSessionAction.PLAY_PAUSE);
-
         if (actions.size() <= COMPACT_VIEW_ACTIONS_COUNT) {
             // If the number of actions is less than |COMPACT_VIEW_ACTIONS_COUNT|, just return an
             // array of 0, 1, ..., |actions.size()|-1.