Fixing duplicate/inconsistent definitions for model and callbacks

> 2 implementations for filtering workspace items
> 2 implementations for binding widgets
> duplicate logic for add and update appInfo

Change-Id: Id68a49926af398478deca8ac85ab1f22341a9449

src/com/android/launcher3/model/AddWorkspaceItemsTask.java

@@ -158,7 +158,7 @@ public class AddWorkspaceItemsTask extends BaseModelUpdateTask {
                         }
                     }
                     callbacks.bindAppsAdded(addedWorkspaceScreensFinal,
-                            addNotAnimated, addAnimated, null);
+                            addNotAnimated, addAnimated);
                 }
             });
         }