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

third_party/WebKit/Source/platform/battery/battery_dispatcher_proxy.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 "platform/battery/battery_dispatcher_proxy.h"
 
 #include "platform/battery/battery_status.h"
 #include "platform/threading/BindForMojo.h"
 #include "public/platform/Platform.h"
+#include "public/platform/ServiceRegistry.h"
 #include "wtf/Assertions.h"
 
 namespace blink {
 
 BatteryDispatcherProxy::BatteryDispatcherProxy(Listener* listener)
     : listener_(listener) {
   ASSERT(listener_);
 }
 
 BatteryDispatcherProxy::~BatteryDispatcherProxy() {}
 
 void BatteryDispatcherProxy::StartListening() {
   ASSERT(!monitor_.is_bound());
-  Platform::current()->connectToRemoteService(mojo::GetProxy(&monitor_));
+  if (!Platform::current()->serviceRegistry())

[esprehn, 2016/03/29 05:26:20]

how do we get here with a null registry? I think that should be a fatal error.
The old code certainly assumed it wasn't possible.

[Sam McNally, 2016/03/30 00:20:53]

The equivalent of a null registry here would have been a no-op
Platform::connectToRemoteService() implementation.

+      return;
+
+  Platform::current()->serviceRegistry()->connectToRemoteService(
+      mojo::GetProxy(&monitor_));
   // monitor_ can be null during testing.
   if (monitor_)
     QueryNextStatus();
 }
 
 void BatteryDispatcherProxy::StopListening() {
   // monitor_ can be null during testing.
   if (monitor_)
     monitor_.reset();
 }
@@ skipping 12 matching lines @@
   DCHECK(battery_status);
 
   BatteryStatus status(battery_status->charging,
                        battery_status->charging_time,
                        battery_status->discharging_time,
                        battery_status->level);
   listener_->OnUpdateBatteryStatus(status);
 }
 
 } // namespace blink