Adding support for multiwindow drag and drop

Change-Id: I95b46e3c3f1238307d3ef5a6c81a8e530ba0987a

src/com/android/launcher3/ButtonDropTarget.java

@@ -259,7 +259,8 @@ public abstract class ButtonDropTarget extends TextView
             }
         };
         dragLayer.animateView(d.dragView, from, to, scale, 1f, 1f, 0.1f, 0.1f,
-                DRAG_VIEW_DROP_DURATION, new DecelerateInterpolator(2),
+                mLauncher.getDragController().isExternalDrag() ? 1 : DRAG_VIEW_DROP_DURATION,
+                new DecelerateInterpolator(2),
                 new LinearInterpolator(), onAnimationEndRunnable,
                 DragLayer.ANIMATION_END_DISAPPEAR, null);
     }