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

components/power/origin_power_map.h

Index: components/power/origin_power_map.h
diff --git a/components/power/origin_power_map.h b/components/power/origin_power_map.h
index 0936be46d8af98264316927e9e404a7bba9da170..5a65fcb62c65ac8d2aed911228e984ea0f2e1ad6 100644
--- a/components/power/origin_power_map.h
+++ b/components/power/origin_power_map.h
@@ -7,7 +7,9 @@
 
 #include <map>
 
+#include "base/observer_list.h"
 #include "components/keyed_service/core/keyed_service.h"
+#include "components/power/origin_power_map_observer.h"
 #include "url/gurl.h"
 
 namespace power {
@@ -33,6 +35,14 @@ class OriginPowerMap : public KeyedService {
   // consumed.
   PercentOriginMap GetPercentOriginMap();
 
+  // Adds/removes observer.
+  void AddObserver(OriginPowerMapObserver* observer);
+  void RemoveObserver(OriginPowerMapObserver* observer);
+
+  // Notifies observers to let them know that the origin power map has finished
+  // updating.
+  void OnPowerConsumptionUpdated();

[Daniel Erat, 2014/08/29 21:14:02]

mind giving this a different name from the OriginPowerMapObserver method to make
it less likely that people will get confused? maybe something like
"OnUpdatesDone" or "OnAllOriginsUpdated"? this also hopefully makes it clearer
that the entire round of updates is done, rather than e.g. this being called
after each AddPowerForOrigin call.

[Daniel Nishi, 2014/09/02 16:30:30]

Done.

+
  private:
   // OriginMap maps a URL to the amount of power consumed by the URL using the
   // same units as |total_consumed_|.
@@ -43,6 +53,8 @@ class OriginPowerMap : public KeyedService {
   // the power heuristics available to the platform.
   double total_consumed_;
 
+  ObserverList<OriginPowerMapObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(OriginPowerMap);
 };