Add blink::ServiceRegistry and expose it from LocalFrame and Platform.

third_party/WebKit/Source/modules/battery/BatteryDispatcher.cpp

 // 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 "modules/battery/BatteryDispatcher.h"
 
 #include "platform/threading/BindForMojo.h"
 #include "public/platform/Platform.h"
+#include "public/platform/ServiceRegistry.h"
 #include "wtf/Assertions.h"
 #include "wtf/PassOwnPtr.h"
 
 namespace blink {
 
 BatteryDispatcher& BatteryDispatcher::instance()
 {
     DEFINE_STATIC_LOCAL(Persistent<BatteryDispatcher>, batteryDispatcher, (new BatteryDispatcher()));
     return *batteryDispatcher;
 }
@@ skipping 27 matching lines @@
 void BatteryDispatcher::updateBatteryStatus(const BatteryStatus& batteryStatus)
 {
     m_batteryStatus = batteryStatus;
     m_hasLatestData = true;
     notifyControllers();
 }
 
 void BatteryDispatcher::startListening()
 {
     ASSERT(!m_monitor.is_bound());
-    Platform::current()->connectToRemoteService(mojo::GetProxy(&m_monitor));
+    if (!Platform::current()->serviceRegistry())

[esprehn, 2016/03/31 05:10:43]

So one thing we could do is have a static EmptyServiceRegistry and make platform
return that by default. Then you're assured it's never null.

[Sam McNally, 2016/03/31 09:26:27]

Done.

+        return;
+
+    Platform::current()->serviceRegistry()->connectToRemoteService(
+        mojo::GetProxy(&m_monitor));
     // m_monitor can be null during testing.
     if (m_monitor)
         queryNextStatus();
 }
 
 void BatteryDispatcher::stopListening()
 {
     // m_monitor can be null during testing.
     if (m_monitor)
         m_monitor.reset();
     m_hasLatestData = false;
 }
 
 } // namespace blink