MediaRouter: Make sure the artview and group list are invalidate

In JB, calling bringToFront() is not enough. Need to make the parent view
invalidate to redraw the widgets properly.

Change-Id: I15af9b177f55c74693220a5e19803c98cb8fe985
diff --git a/v7/mediarouter/src/android/support/v7/app/MediaRouteControllerDialog.java b/v7/mediarouter/src/android/support/v7/app/MediaRouteControllerDialog.java
index 31ae4b5..6fea258 100644
--- a/v7/mediarouter/src/android/support/v7/app/MediaRouteControllerDialog.java
+++ b/v7/mediarouter/src/android/support/v7/app/MediaRouteControllerDialog.java
@@ -588,7 +588,9 @@
         final boolean isExpanding = bottomMargin != 0;
         if (!animation) {
             setLayoutBottomMargin(mMediaMainControlLayout, bottomMargin);
-            (isExpanding ? mVolumeGroupList : mArtView).bringToFront();
+            View frontView = isExpanding ? mVolumeGroupList : mArtView;
+            frontView.bringToFront();
+            ((View) frontView.getParent()).invalidate();
         } else {
             Animation existingAnim = mMediaMainControlLayout.getAnimation();
             boolean animationInProgress = existingAnim != null && !existingAnim.hasEnded();
@@ -616,11 +618,13 @@
                         if (isExpanding) {
                             if (margin + mainControllerHeight >= volumeGroupListHeight) {
                                 mVolumeGroupList.bringToFront();
+                                ((View) mVolumeGroupList.getParent()).invalidate();
                                 mReordered = true;
                             }
                         } else {
                             if (volumeGroupListHeight >= margin + mainControllerHeight) {
                                 mArtView.bringToFront();
+                                ((View) mArtView.getParent()).invalidate();
                                 mReordered = true;
                             }
                         }