[Offline pages] Updates to background scheduling to use BTS

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerProcessor.java

+// Copyright 2016 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.chrome.browser.offlinepages;
+
+import org.chromium.base.Callback;
+import org.chromium.base.VisibleForTesting;
+
+/** Class allowing for mocking out calls to BackgroundSchedulerBridge.  */
+public class BackgroundSchedulerProcessor {
+    private static BackgroundSchedulerProcessor sInstance;
+
+    /** Returns a singleton instance. */
+    public static BackgroundSchedulerProcessor getInstance() {
+        if (sInstance == null) {
+            sInstance = new BackgroundSchedulerProcessor();
+        }
+        return sInstance;
+    }
+
+    @VisibleForTesting
+    static void setInstanceForTesting(BackgroundSchedulerProcessor instance) {
+        sInstance = instance;
+    }
+
+    /**
+     * Starts processing of one or more queued background requests.  Returns whether processing was
+     * started and that caller should expect a callback (once processing has completed or
+     * terminated).  If processing was already active or not able to process for some other reason,
+     * returns false and this calling instance will not receive a callback.
+     */
+    public boolean startScheduledProcessing(
+            DeviceConditions deviceConditions, Callback<Boolean> callback) {
+        return BackgroundSchedulerBridge.startScheduledProcessing(deviceConditions, callback);
+    }
+
+    /**
+     * Stops processing background requests.
+     * @return Whether processing should be scheduled again at a later time, because there is more
+     * work.
+     */
+    public boolean stopScheduledProcessing() {
+        return BackgroundSchedulerBridge.stopScheduledProcessing();
+    }
+}