[Re-land] Add network throttling as enterprise policy

chrome/browser/chromeos/net/network_throttling_observer.h

+// Copyright 2016 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_NET_NETWORK_THROTTLING_OBSERVER_H_
+#define CHROME_BROWSER_CHROMEOS_NET_NETWORK_THROTTLING_OBSERVER_H_
+
+#include <string>
+
+#include "base/memory/weak_ptr.h"
+#include "components/prefs/pref_change_registrar.h"
+
+class PrefRegistrySimple;
+class Profile;
+
+namespace chromeos {
+
+// NetworkThrottlingObserver is a singleton, owned by
+// ChromeBrowserMainPartsChromeos.
+// This class is responsible for propagating network bandwidth throttling policy
+// changes (prefs::kNetworkThrottlingEnabled) in Chrome down to Shill which
+// implements by calling 'tc' in the kernel.
+class NetworkThrottlingObserver {
+ public:
+  explicit NetworkThrottlingObserver(PrefService* local_state);
+  ~NetworkThrottlingObserver();
+
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+ private:
+  // Callback used when prefs::kNetworkThrottlingEnabled changes
+  void OnPreferenceChanged(const std::string& pref_name);
+
+  PrefService* local_state_;
+  PrefChangeRegistrar pref_change_registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkThrottlingObserver);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_NET_NETWORK_THROTTLING_OBSERVER_H_