Add required cast

Change-Id: I6ff78f583777ec71d414d2fa66cce3390fd97d0e
diff --git a/src/com/android/launcher3/InfoDropTarget.java b/src/com/android/launcher3/InfoDropTarget.java
index fb623ca..c8541a9 100644
--- a/src/com/android/launcher3/InfoDropTarget.java
+++ b/src/com/android/launcher3/InfoDropTarget.java
@@ -52,7 +52,7 @@
 
         if (mDrawable == null) {
             // TODO: investigate why this is ever happening. Presently only on one known device.
-            mDrawable = r.getDrawable(R.drawable.info_target_selector);
+            mDrawable = (TransitionDrawable) r.getDrawable(R.drawable.info_target_selector);
             setCompoundDrawablesRelativeWithIntrinsicBounds(mDrawable, null, null, null);
         }