Use Launcher.getLauncher(Context) instead of type-casting.

Bug: 32010039
Change-Id: Icb80d3e547a706740b84df2cb80f99e4a7f81c43
diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index bea55d2..e380e26 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -1834,7 +1834,7 @@
     }
 
     protected void onUnhandledTap(MotionEvent ev) {
-        ((Launcher) getContext()).onClick(this);
+        Launcher.getLauncher(getContext()).onClick(this);
     }
 
     @Override