Stop using [Client=...] feature of Mojom for BatteryMonitor

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) {
+    : binding_(this),
+      listener_(listener) {
   DCHECK(listener_);
 
   RenderThread::Get()->GetServiceRegistry()->ConnectToRemoteService(&monitor_);

[jamesr, 2015/01/05 23:33:09]

i'm not as familiar with content::'s service registry hookup, but it feels weird
to first have this code connect to a named Service only to tell it to set a
client back.  Can we instead just ask the service to connect to us directly and
cut out the Client thingy completely?

In the pure-mojo world, this would work by connecting to the battery monitor
service (by url) and then exposing a monitor interface on the service provider
that's provided to the battery monitor.  so the mojo messages for 'app' to start
listening to battery status updates would be:

app->shell ConnectToApplication("mojo:battery_status", ..)
shell->battery_status_service AcceptConnection(app_url, ...)
battery_status_service->app ConnectToService("device.BatteryMonitor", ...) (via
the mojo.ServiceProvider pipe)
battery_status_service->app DidChange(xxx) (via the device.BatteryMonitor pipe)

-  monitor_.set_client(this);
+
+  device::BatteryMonitorClientPtr proxy;
+  binding_.Bind(&proxy);
+  monitor_->SetClient(proxy.Pass());
 }
 
 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