Add Origin Power Map to Store Battery Auditing Data.

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 "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;
+
+  OriginPowerMap();
+  virtual ~OriginPowerMap();
+
+  // Returns the integer percentage usage of the total power consumed by a
+  // given URL's origin.
+  int GetPowerForOrigin(const GURL& url);
+
+  // Add a certain amount of power consumption to a given URL's origin.

[Daniel Erat, 2014/08/12 15:58:52]

nit: s/Add/Adds/

[Daniel Nishi, 2014/08/12 17:33:46]

Done.

+  // |power| is a platform-specific heuristic estimating power consumption.
+  void AddPowerForOrigin(const GURL& url, double power);
+
+  // Return a map of all origins to the integer percentage usage of power

[Daniel Erat, 2014/08/12 15:58:52]

nit: s/Return/Returns/

[Daniel Nishi, 2014/08/12 17:33:46]

Done.

+  // consumed.
+  scoped_ptr<PercentOriginMap> GetPercentOriginMap();

[Daniel Erat, 2014/08/12 15:58:52]

does this need to be scoped_ptr? i'm wondering if we can just depend on
http://en.wikipedia.org/wiki/Return_value_optimization here.

[Daniel Nishi, 2014/08/12 17:33:46]

I didn't do any formal profiling, but my unittests don't run any slower with
just returning the value.

I'll just return the value and rely on that.

+
+ private:
+  typedef std::map<GURL, double> OriginMap;

[Daniel Erat, 2014/08/12 15:58:52]

nit: add a comment documenting what the doubles are here ([0.0, 100.0]? [0.0,
1.0]? fractions of |total_consumed_|, or actual power consumed?

[Daniel Nishi, 2014/08/12 17:33:46]

Done.

+  OriginMap origin_map_;
+
+  // The total amount of power consumed since the last wipe.

[Daniel Erat, 2014/08/12 15:58:52]

when do "wipes" happen? i don't see |total_consumed_| getting reset in the
implementation. does the entire OriginPowerMap get thrown away periodically?

[Daniel Nishi, 2014/08/12 17:33:46]

Since the data is not currently persisted, this will occur when the browser
shuts down.

That said, we want battery persistence of some sort in the future and the exact
invalidation spec is being discussed on the design doc.

+  double total_consumed_;
+
+  DISALLOW_COPY_AND_ASSIGN(OriginPowerMap);
+};
+
+}  // namespace power
+
+#endif  // COMPONENTS_POWER_ORIGIN_POWER_MAP_H_