Update the Website Settings page when the power consumption is updated.

components/power/origin_power_map.h

 // 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.
 
 #ifndef COMPONENTS_POWER_ORIGIN_POWER_MAP_H_
 #define COMPONENTS_POWER_ORIGIN_POWER_MAP_H_
 
 #include <map>
 
+#include "base/callback_list.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "url/gurl.h"
 
 namespace power {
 
 // Tracks app and website origins and how much power they are consuming while
 // running.
 class OriginPowerMap : public KeyedService {
  public:
   typedef std::map<GURL, int> PercentOriginMap;
+  typedef base::CallbackList<void(void)>::Subscription Subscription;
 
   OriginPowerMap();
   virtual ~OriginPowerMap();
 
   // Returns the integer percentage usage of the total power consumed by a
   // given URL's origin.
   int GetPowerForOrigin(const GURL& url);
 
   // Adds a certain amount of power consumption to a given URL's origin.
   // |power| is a platform-specific heuristic estimating power consumption.
   void AddPowerForOrigin(const GURL& url, double power);
 
   // Returns a map of all origins to the integer percentage usage of power
   // consumed.
   PercentOriginMap GetPercentOriginMap();
 
+  // Adds a callback for when the power consumption for the map finishes

[Daniel Erat, 2014/09/02 17:14:39]

nit: maybe something like "Adds a callback for the completion of a round of
updates to |origin_map_|."

[Daniel Nishi, 2014/09/02 17:32:48]

Done.

+  // updating.
+  scoped_ptr<Subscription> AddPowerConsumptionUpdatedCallback(
+      const base::Closure& callback);
+
+  // Notifies observers to let them know that the origin power map has finished
+  // updating for all origins this cycle.
+  void OnAllOriginsUpdated();
+
  private:
   // OriginMap maps a URL to the amount of power consumed by the URL using the
   // same units as |total_consumed_|.
   typedef std::map<GURL, double> OriginMap;
   OriginMap origin_map_;
 
   // Total amount of power consumed using units determined by
   // the power heuristics available to the platform.
   double total_consumed_;
 
+  base::CallbackList<void(void)> callback_list_;
+
   DISALLOW_COPY_AND_ASSIGN(OriginPowerMap);
 };
 
 }  // namespace power
 
 #endif  // COMPONENTS_POWER_ORIGIN_POWER_MAP_H_