Add service unittest for WakeLockServiceImpl.

device/wake_lock/wake_lock_provider.h

 // 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.
 
 #ifndef DEVICE_WAKE_LOCK_WAKE_LOCK_PROVIDER_H_
 #define DEVICE_WAKE_LOCK_WAKE_LOCK_PROVIDER_H_
 
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
 #include "device/wake_lock/public/interfaces/wake_lock_context.mojom.h"
@@ skipping 20 matching lines @@
   void GetWakeLockContextForID(
       int context_id,
       mojo::InterfaceRequest<mojom::WakeLockContext> request) override;
 
   void GetWakeLockWithoutContext(
       mojom::WakeLockType type,
       mojom::WakeLockReason reason,
       const std::string& description,
       mojom::WakeLockServiceRequest request) override;
 
+  static bool is_in_service_unittest_;
+
  private:
   scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
   WakeLockContextCallback native_view_getter_;
 
   DISALLOW_COPY_AND_ASSIGN(WakeLockProvider);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_WAKE_LOCK_WAKE_LOCK_PROVIDER_H_