Refactoring ItemInfo

> Changing dragObject to ItemInfo
> Removing dropPos which is always null
> Removing requiresDbUpdate which is only used in CellLayout

Change-Id: I753ddaae0880c8a9bfee5a1266095ff34610284a
diff --git a/src/com/android/launcher3/Folder.java b/src/com/android/launcher3/Folder.java
index 85f58a1..fbb2394 100644
--- a/src/com/android/launcher3/Folder.java
+++ b/src/com/android/launcher3/Folder.java
@@ -598,7 +598,7 @@
     }
 
     @Override
-    public void onDragStart(DragSource source, Object info, int dragAction) { }
+    public void onDragStart(DragSource source, ItemInfo info, int dragAction) { }
 
     @Override
     public void onDragEnd() {
@@ -647,7 +647,7 @@
     }
 
     public boolean acceptDrop(DragObject d) {
-        final ItemInfo item = (ItemInfo) d.dragInfo;
+        final ItemInfo item = d.dragInfo;
         final int itemType = item.itemType;
         return ((itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION ||
                     itemType == LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT) &&