Bug 1329122 - should unregister agent when media element becomes inactive. r=baku

We should remove the media control interface immediately when the document is inacitve, even it was paused by media control before.

MozReview-Commit-ID: GBDhzEFOTXE

dom/html/HTMLMediaElement.cpp

@@ -1030,6 +1030,11 @@ private:
       return false;
     }
 
+    // We should consider any bfcached page or inactive document as non-playing.
+    if (!mOwner->IsActive()) {
+      return false;
+    }
+
     // It might be resumed from remote, we should keep the audio channel agent.
     if (IsSuspended()) {
       return true;
@@ -1040,11 +1045,6 @@ private:
       return false;
     }
 
-    // We should consider any bfcached page or inactive document as non-playing.
-    if (!mOwner->IsActive()) {
-      return false;
-    }
-
     // A loop always is playing
     if (mOwner->HasAttr(kNameSpaceID_None, nsGkAtoms::loop)) {
       return true;