[Android] Adding scheduling through GcmNetworkManager

components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/ShadowGcmNetworkManager.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 com.google.android.gms.gcm.GcmNetworkManager;
+import com.google.android.gms.gcm.GcmTaskService;
+import com.google.android.gms.gcm.Task;
+
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
+
+/**
+ * Custom shadow for the OS's GcmNetworkManager.  We use this to hook the call to GcmNetworkManager
+ * to make sure it was invoked as we expect.
+ */
+@Implements(GcmNetworkManager.class)
+public class ShadowGcmNetworkManager {
+    private Task mTask;
+    private Task mCanceledTask;
+
+    @Implementation
+    public void schedule(Task task) {
+        mTask = task;
+        mCanceledTask = null;
+    }
+
+    @Implementation
+    public void cancelTask(String tag, Class<? extends GcmTaskService> gcmTaskService) {
+        if (mTask != null && mTask.getTag().equals(tag)
+                && mTask.getServiceName().equals(gcmTaskService.getName())) {
+            mCanceledTask = mTask;
+            mTask = null;
+        }
+    }
+
+    public Task getScheduledTask() {
+        return mTask;
+    }
+
+    public Task getCanceledTask() {
+        return mCanceledTask;
+    }
+
+    public void clear() {
+        mTask = null;
+        mCanceledTask = null;
+    }
+}