Caching last predictions and loading it with model

Adding support for persisting itemInfos on disk. This uses
a separate xml file. Unlike prefs, it does not keep the items
in memory and is just a wraper over reading/writing a file.

Bug: 160748731
Change-Id: Iaccab9928ab8f30127fb3c2d630ca8ca83f0bd05

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

@@ -18,13 +18,17 @@ package com.android.launcher3.model;
 import static com.android.launcher3.util.PackageManagerHelper.hasShortcutsPermission;
 
 import android.content.Context;
+import android.content.pm.ShortcutInfo;
 
 import androidx.annotation.WorkerThread;
 
 import com.android.launcher3.LauncherAppState;
 import com.android.launcher3.R;
+import com.android.launcher3.shortcuts.ShortcutKey;
 import com.android.launcher3.util.ResourceBasedOverride;
 
+import java.util.Map;
+
 /**
  * Class to extend LauncherModel functionality to provide extra data
  */
@@ -65,11 +69,12 @@ public class ModelDelegate implements ResourceBasedOverride {
      * Load delegate items if any in the data model
      */
     @WorkerThread
-    public void loadItems() { }
+    public void loadItems(UserManagerState ums, Map<ShortcutKey, ShortcutInfo> pinnedShortcuts) { }
 
     /**
      * Called when the delegate is no loner needed
      */
     @WorkerThread
     public void destroy() { }
+
 }