chromeos: Delete obsolete power_prefs files.

Remove power_prefs.h and power_prefs_unittest.cc files that
I think were accidentally missed when r549765 moved code
from //chrome to //ash.

Bug: 812504
Change-Id: Ic83f1d400742321756b09f9f2cc9cc738883f2bd
Reviewed-on: https://chromium-review.googlesource.com/1164410Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581038}

chrome/browser/chromeos/power/power_prefs.h

-// Copyright 2013 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 CHROME_BROWSER_CHROMEOS_POWER_POWER_PREFS_H_
-#define CHROME_BROWSER_CHROMEOS_POWER_POWER_PREFS_H_
-
-#include <memory>
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "base/scoped_observer.h"
-#include "base/time/tick_clock.h"
-#include "chromeos/dbus/power_manager_client.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-
-class PrefChangeRegistrar;
-class Profile;
-
-namespace power_manager {
-class ScreenIdleState;
-}
-
-namespace user_prefs {
-class PrefRegistrySyncable;
-}
-
-namespace chromeos {
-
-class PowerPolicyController;
-
-// Sends an updated power policy to the |power_policy_controller| whenever one
-// of the power-related prefs changes.
-class PowerPrefs : public PowerManagerClient::Observer,
-                   public content::NotificationObserver {
- public:
-  PowerPrefs(PowerPolicyController* power_policy_controller,
-             PowerManagerClient* power_manager_client);
-  ~PowerPrefs() override;
-
-  // Register power prefs with default values applicable to a user profile.
-  static void RegisterUserProfilePrefs(
-      user_prefs::PrefRegistrySyncable* registry);
-
-  // Register power prefs with default values applicable to the login profile.
-  static void RegisterLoginProfilePrefs(
-      user_prefs::PrefRegistrySyncable* registry);
-
-  void set_tick_clock_for_test(const base::TickClock* clock) {
-    tick_clock_ = clock;
-  }
-
-  // PowerManagerClient::Observer:
-  void ScreenIdleStateChanged(
-      const power_manager::ScreenIdleState& proto) override;
-
-  // content::NotificationObserver:
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
-  void UpdatePowerPolicyFromPrefs();
-
- private:
-  friend class PowerPrefsTest;
-
-  // Register power prefs whose default values are the same in user profiles and
-  // the login profile.
-  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
-
-  void SetProfile(Profile* profile);
-
-  PowerPolicyController* power_policy_controller_;  // Not owned.
-
-  content::NotificationRegistrar notification_registrar_;
-
-  ScopedObserver<PowerManagerClient, PowerManagerClient::Observer>
-      power_manager_client_observer_;
-
-  Profile* profile_ = nullptr;  // Not owned.
-  std::unique_ptr<PrefChangeRegistrar> pref_change_registrar_;
-
-  const base::TickClock* tick_clock_;  // Not owned.
-
-  // Time at which the screen was locked. Unset if the screen is unlocked.
-  base::TimeTicks screen_lock_time_;
-
-  // Time at which the screen was last turned off due to user inactivity.
-  // Unset if the screen isn't currently turned off due to user inactivity.
-  base::TimeTicks screen_idle_off_time_;
-
-  DISALLOW_COPY_AND_ASSIGN(PowerPrefs);
-};
-
-}  // namespace chromeos
-
-#endif  // CHROME_BROWSER_CHROMEOS_POWER_POWER_PREFS_H_