[Android] BackgroundTaskScheduler reschedule implementation

components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTask.java

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.components.background_task_scheduler;
 
 import android.content.Context;
 import android.support.annotation.AnyThread;
 import android.support.annotation.MainThread;
 
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      *
      * @param context the current context.
      * @param taskParameters the data passed in as {@link TaskInfo} when the task was scheduled.
      * @return true if the task needs to be rescheduled according to the rescheduling criteria
      * specified when the task was scheduled initially. False if the taskshould not be rescheduled.
      * Regardless of the value returned, your task must stop executing.
      * @see TaskInfo
      */
     @MainThread
     boolean onStopTask(Context context, TaskParameters taskParameters);
+
+    /**
+     * Callback from {@link BackgroundTaskScheduler} when it detects system conditions requiring
+     * rescheduling, e.g. Google Play Services update or OS upgrade. The task should schedule itself
+     * again with appropriate parameters.
+     *
+     * @param context the current context.
+     */
+    @MainThread
+    void reschedule(Context context);
 }