Add network throttling as an 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 "base/memory/weak_ptr.h"
+
+class PrefRegistrySimple;
+class Profile;
+
+namespace chromeos {
+
+namespace network_throttling_observer {
+
+void RegisterPrefs(PrefRegistrySimple* registry);
+}
+
+// Helper class that listens for changes in network throttling
+// policy, and propagates them down to shill (the network manager).
+// Call-flow: NetworkThrottlingObserver
+//            -> NetworkStateHandler
+//            -> ShillManagerClient
+class NetworkThrottlingObserver {

[Andrew T Wilson (Slow), 2016/10/21 13:27:30]

This is a weird class - it's owned by ChromeBrowserParts but has a getter here,
so it's kind of a singleton owned by ChromeBrowserParts. You really need to
document the lifetime and purpose of the getter below better than this.

[stevenjb, 2016/10/21 19:41:20]

+1. We generally use one of two patterns:

1) The class is owned by ChromeBrowserMainParts and passed to any other classes
that need to access it. This is generally preferred, but sometimes inconvenient
for classes that are accessed frequently.

2) The class has static Initialize(), Shutdown(), and Get() methods that manage
the global instance. Initialize() and Shutdown() is called in
ChromeBrowserMainParts(). Get() should assert if the instance is uninitailized.
e.g. see NetworkHandler.

[stevenjb, 2016/10/21 20:25:54]

If we make this a pref observer we shouldn't need Get() at all since this class
will register itself as a pref observer on construction and OnPreferenceChanged
does not need to be called explicitly.

[kirtika1, 2016/10/23 00:04:49]

Done, used (1)

[kirtika1, 2016/10/23 00:04:49]

Thanks for that suggestion!Done.

+ public:
+  NetworkThrottlingObserver();
+  ~NetworkThrottlingObserver();
+
+  static NetworkThrottlingObserver* Get();
+
+  // Should be called whenever the network throttling policy changes
+  void OnPreferenceChanged(bool throttling_enabled,
+                           uint32_t upload_rate_kbits,
+                           uint32_t download_rate_kbits);
+
+ private:
+  base::WeakPtrFactory<NetworkThrottlingObserver> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkThrottlingObserver);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_NET_NETWORK_THROTTLING_OBSERVER_H_