Moving drag-drop related code into a separate package.

This is per an earlier CR comment "we should probably move all this code to its own package (launcher3.dragndrop) in a separate cl".

I'm not moving DragSource because it's referred from gsa code.

Bug: 22609426
Change-Id: Ia7204dab99c0c395c66b77143a2d60411153f5f3

src/com/android/launcher3/ShortcutInfo.java

@@ -70,7 +70,7 @@ public class ShortcutInfo extends ItemInfo {
     /**
      * The intent used to start the application.
      */
-    Intent intent;
+    public Intent intent;
 
     /**
      * Indicates whether the icon comes from an application's resource (if false)