Pause EME player whose external surface is stolen by another player

android_webview/java/src/org/chromium/android_webview/ExternalVideoSurfaceContainer.java

Index: android_webview/java/src/org/chromium/android_webview/ExternalVideoSurfaceContainer.java
diff --git a/android_webview/java/src/org/chromium/android_webview/ExternalVideoSurfaceContainer.java b/android_webview/java/src/org/chromium/android_webview/ExternalVideoSurfaceContainer.java
index 0631be66b9a1301ca712a897bff310e007106210..45e7af75b58b1a383c74a1d478e39da323f0a251 100644
--- a/android_webview/java/src/org/chromium/android_webview/ExternalVideoSurfaceContainer.java
+++ b/android_webview/java/src/org/chromium/android_webview/ExternalVideoSurfaceContainer.java
@@ -123,6 +123,8 @@ public class ExternalVideoSurfaceContainer implements SurfaceHolder.Callback {
      */
     @CalledByNative
     protected void requestExternalVideoSurface(int playerId) {
+        assert playerId != INVALID_PLAYER_ID;
+
         if (mPlayerId == playerId) return;
 
         setActiveContainer(this);
@@ -134,6 +136,14 @@ public class ExternalVideoSurfaceContainer implements SurfaceHolder.Callback {
     }
 
     /**
+     * Returns id of player currently using the external video surface.
+     */
+    @CalledByNative
+    protected int getCurrentPlayerId() {
+        return mPlayerId;
+    }
+
+    /**
      * Called when a media player wants to release an external video surface.
      * @param playerId The ID of the media player.
      */