Add Data Saver support to Cronet

components/cronet/android/cronet_pref_store.h

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Copyright 2015 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 ANDROID_WEBVIEW_BROWSER_AW_PREF_STORE_H_
-#define ANDROID_WEBVIEW_BROWSER_AW_PREF_STORE_H_
+#ifndef COMPONENTS_CRONET_ANDROID_CRONET_PREF_STORE_H_
+#define COMPONENTS_CRONET_ANDROID_CRONET_PREF_STORE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/observer_list.h"
 #include "base/prefs/persistent_pref_store.h"
 #include "base/prefs/pref_value_map.h"
 
 // A light-weight prefstore implementation that keeps preferences
 // in a memory backed store. This is not a persistent prefstore -- we
 // subclass the PersistentPrefStore here since it is needed by the
 // PrefService, which in turn is needed by the Autofill component.

[xunjieli, 2015/03/20 18:39:49]

I am not sure "Autofill" component is applicable in the context of Cronet. Maybe
removing the part from the comment?

[bengr, 2015/04/24 02:30:42]

Done.

-class AwPrefStore : public PersistentPrefStore {
+// TODO(bengr): Move to base/prefs or some other shared location.
+class CronetPrefStore : public PersistentPrefStore {

[xunjieli, 2015/03/20 18:39:49]

I am working on persisting HttpServerProperties on disk through the use of
HttpServerPropertiesManager and PrefStore. I heard that SDCH will be using
PrefStore as well. 

Maybe rename this class to something like CronetInMemoryPrefStore? since there
Cronet will be using other kinds of pref store.

Just curious, I don't know much about data reduction proxy, will it ever need
persisting info on disk? or this memory backed pref store is enough?

[bengr, 2015/04/24 02:30:42]

The pref store for the data reduction proxy holds some statistics, which Cronet
doesn't use yet. We're considering two models for using them, and the more
popular one would not require on disk persistence.

  public:
-  AwPrefStore();
+  CronetPrefStore();
 
-  // Overriden from PrefStore.
+  // Overrides from PrefStore:
   bool GetValue(const std::string& key,
                 const base::Value** result) const override;
   void AddObserver(PrefStore::Observer* observer) override;
   void RemoveObserver(PrefStore::Observer* observer) override;
   bool HasObservers() const override;
   bool IsInitializationComplete() const override;
 
   // PersistentPrefStore overrides:
-  bool GetMutableValue(const std::string& key, base::Value** result) override;
+  bool GetMutableValue(const std::string& key,
+                       base::Value** result) override;
   void ReportValueChanged(const std::string& key) override;
   void SetValue(const std::string& key, base::Value* value) override;
-  void SetValueSilently(const std::string& key, base::Value* value) override;
+  void SetValueSilently(const std::string& key,
+                                base::Value* value) override;
   void RemoveValue(const std::string& key) override;
   bool ReadOnly() const override;
   PrefReadError GetReadError() const override;
   PersistentPrefStore::PrefReadError ReadPrefs() override;
   void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
   void CommitPendingWrite() override {}
 
  protected:
-  ~AwPrefStore() override;
+  ~CronetPrefStore() override;
 
  private:
   // Stores the preference values.
   PrefValueMap prefs_;
 
   ObserverList<PrefStore::Observer, true> observers_;
 
-  DISALLOW_COPY_AND_ASSIGN(AwPrefStore);
+  DISALLOW_COPY_AND_ASSIGN(CronetPrefStore);
 };
 
-#endif  // ANDROID_WEBVIEW_BROWSER_AW_PREF_STORE_H_
+#endif  // COMPONENTS_CRONET_ANDROID_CRONET_PREF_STORE_H_