Change home dragging logic for dead zones

- If a dragged item is not over a valid drop target
then we don't highlight anything and on drop we move
it back to its original position.
- Instead of checking if the dragged item is over the
hotseat view, now we check if the item is over the hotseat
shortcuts.
- Smartspace is a dead zone

Test: drag items from different workspaces, allapps, widget
  picker etc. to all parts of the screen and verify which
  view is targeted and where the item gets dropped.
  Check on phone/foldable/tablet.
Bug: 228201267
Change-Id: I18de576ea300d58ae645e511b238e0b946b5595a

src/com/android/launcher3/Utilities.java

@@ -272,6 +272,16 @@ public final class Utilities {
                 Math.max(points[1], points[3]));
     }
 
+    /**
+     * Similar to {@link #mapCoordInSelfToDescendant(View descendant, View root, float[] coord)}
+     * but accepts a Rect instead of float[].
+     */
+    public static void mapRectInSelfToDescendant(View descendant, View root, Rect rect) {
+        float[] coords = new float[]{rect.left, rect.top, rect.right, rect.bottom};
+        mapCoordInSelfToDescendant(descendant, root, coords);
+        rect.set((int) coords[0], (int) coords[1], (int) coords[2], (int) coords[3]);
+    }
+
     /**
      * Inverse of {@link #getDescendantCoordRelativeToAncestor(View, View, float[], boolean)}.
      */