Bug 1357639 - part8 : add annotiation @RobocopTarget. r=sebastian

To make sure these functions can be used in robocop test.

MozReview-Commit-ID: KPAKOrg5Ows

--HG--
extra : rebase_source : 13632cef16c96457ce77c01bc4330a9793ab83ad

mobile/android/base/java/org/mozilla/gecko/Tabs.java

@@ -963,6 +963,7 @@ public class Tabs implements BundleEventListener {
      *
      * @return first Tab with the given URL, or null if there is no such tab.
      */
+    @RobocopTarget
     public Tab getFirstTabForUrl(String url) {
         return getFirstTabForUrlHelper(url, null, TabType.BROWSING);
     }

mobile/android/base/java/org/mozilla/gecko/media/AudioFocusAgent.java

@@ -146,11 +146,13 @@ public class AudioFocusAgent {
     }
 
     @VisibleForTesting
+    @RobocopTarget
     public State getAudioFocusState() {
         return mAudioFocusState;
     }
 
     @VisibleForTesting
+    @RobocopTarget
     public void changeAudioFocus(int focusChange) {
         mAfChangeListener.onAudioFocusChange(focusChange);
     }