Resurrect battery_status_dispatcher_unittest.

content/renderer/battery_status/battery_status_dispatcher.cc

 // Copyright 2014 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.
 
 #include "content/renderer/battery_status/battery_status_dispatcher.h"
 
 #include "content/public/common/service_registry.h"
 #include "content/public/renderer/render_thread.h"
 #include "third_party/WebKit/public/platform/WebBatteryStatusListener.h"
 
 namespace content {
 
 BatteryStatusDispatcher::BatteryStatusDispatcher(
     blink::WebBatteryStatusListener* listener)
     : listener_(listener) {
   DCHECK(listener_);
 
-  RenderThread::Get()->GetServiceRegistry()->ConnectToRemoteService(&monitor_);
-  monitor_.set_client(this);
+  if (ServiceRegistry* registry = RenderThread::Get()->GetServiceRegistry()) {
+    // registry can be null during testing.
+    registry->ConnectToRemoteService(&monitor_);
+    monitor_.set_client(this);
+  }
 }
 
 BatteryStatusDispatcher::~BatteryStatusDispatcher() {
 }
 
 void BatteryStatusDispatcher::DidChange(
     device::BatteryStatusPtr battery_status) {
   DCHECK(battery_status);
   blink::WebBatteryStatus web_battery_status;
   web_battery_status.charging = battery_status->charging;
   web_battery_status.chargingTime = battery_status->charging_time;
   web_battery_status.dischargingTime = battery_status->discharging_time;
   web_battery_status.level = battery_status->level;
   listener_->updateBatteryStatus(web_battery_status);
 }
 
 }  // namespace content