RingtonePickerActivity: Keep cursor open while visible.

If we clear the cursor before we are actually invisible we
may do so during or right before the exit animation
and see weird results (in this case a copy of the dialog
which contains no ringtones).

Bug: 26972412
Change-Id: I48b2f4ca5a677085c718f6c7866b3b6d1ca03689

src/com/android/providers/media/RingtonePickerActivity.java

@@ -282,12 +282,6 @@ public final class RingtonePickerActivity extends AlertActivity implements
             setResult(RESULT_CANCELED);
         }
 
-        getWindow().getDecorView().post(new Runnable() {
-            public void run() {
-                mCursor.deactivate();
-            }
-        });
-
         finish();
     }
 
@@ -346,6 +340,8 @@ public final class RingtonePickerActivity extends AlertActivity implements
     @Override
     protected void onStop() {
         super.onStop();
+        mCursor.deactivate();
+
         if (!isChangingConfigurations()) {
             stopAnyPlayingRingtone();
         } else {