Add AsyncTask back and deprecate

Author: RHenigan

base/src/main/java/android/os/AsyncTask.java

@@ -0,0 +1,26 @@
+ /*
+  * Copyright (C) 2008 The Android Open Source Project
+  *
+  * Licensed under the Apache License, Version 2.0 (the "License");
+  * you may not use this file except in compliance with the License.
+  * You may obtain a copy of the License at
+  *
+  *      http://www.apache.org/licenses/LICENSE-2.0
+  *
+  * Unless required by applicable law or agreed to in writing, software
+  * distributed under the License is distributed on an "AS IS" BASIS,
+  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  * See the License for the specific language governing permissions and
+  * limitations under the License.
+  *
+  * Note: This file has been modified from its original form.
+  */
+ 
+package android.os;
+
+public abstract class AsyncTask<Params, Progress, Result> {
+
+
+    abstract protected Result doInBackground(Params...params);
+
+}