[DeviceService] Add end-to-end browsertest for PowerMonitor

content/public/test/power_monitor_test.mojom

Index: content/public/test/power_monitor_test.mojom
diff --git a/content/public/test/power_monitor_test.mojom b/content/public/test/power_monitor_test.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..59211cb7eb830a8abbb36de9d6fb5b755bf6d774
--- /dev/null
+++ b/content/public/test/power_monitor_test.mojom
@@ -0,0 +1,9 @@
+// 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.
+
+module content.mojom;
+
+interface PowerMonitorTest {

[blundell, 2017/05/16 13:28:42]

nit: This could use a comment.

[jam, 2017/06/06 22:20:28]

nit: move this to content/shell/common

[leonhsl(Using Gerrit), 2017/06/09 07:05:53]

Done.

[leonhsl(Using Gerrit), 2017/06/09 07:05:53]

Done.

+  QueryNextState() => (bool on_battery_power);
+};