Revert of Move base/prefs to components/prefs

components/prefs/writeable_pref_store.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 BASE_PREFS_WRITEABLE_PREF_STORE_H_
-#define BASE_PREFS_WRITEABLE_PREF_STORE_H_
-
-#include <stdint.h>
-
-#include <string>
-
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/prefs/pref_store.h"
-
-namespace base {
-class Value;
-}
-
-// A pref store that can be written to as well as read from.
-class BASE_PREFS_EXPORT WriteablePrefStore : public PrefStore {
- public:
-  // PrefWriteFlags can be used to change the way a pref will be written to
-  // storage.
-  enum PrefWriteFlags : uint32_t {
-    // No flags are specified.
-    DEFAULT_PREF_WRITE_FLAGS = 0,
-
-    // This marks the pref as "lossy". There is no strict time guarantee on when
-    // a lossy pref will be persisted to permanent storage when it is modified.
-    LOSSY_PREF_WRITE_FLAG = 1 << 1
-  };
-
-  WriteablePrefStore() {}
-
-  // Sets a |value| for |key| in the store. |value| must be non-NULL. |flags| is
-  // a bitmask of PrefWriteFlags.
-  virtual void SetValue(const std::string& key,
-                        scoped_ptr<base::Value> value,
-                        uint32_t flags) = 0;
-
-  // Removes the value for |key|.
-  virtual void RemoveValue(const std::string& key, uint32_t flags) = 0;
-
-  // Equivalent to PrefStore::GetValue but returns a mutable value.
-  virtual bool GetMutableValue(const std::string& key,
-                               base::Value** result) = 0;
-
-  // Triggers a value changed notification. This function needs to be called
-  // if one retrieves a list or dictionary with GetMutableValue and change its
-  // value. SetValue takes care of notifications itself. Note that
-  // ReportValueChanged will trigger notifications even if nothing has changed.
-  // |flags| is a bitmask of PrefWriteFlags.
-  virtual void ReportValueChanged(const std::string& key, uint32_t flags) = 0;
-
-  // Same as SetValue, but doesn't generate notifications. This is used by
-  // PrefService::GetMutableUserPref() in order to put empty entries
-  // into the user pref store. Using SetValue is not an option since existing
-  // tests rely on the number of notifications generated. |flags| is a bitmask
-  // of PrefWriteFlags.
-  virtual void SetValueSilently(const std::string& key,
-                                scoped_ptr<base::Value> value,
-                                uint32_t flags) = 0;
-
- protected:
-  ~WriteablePrefStore() override {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(WriteablePrefStore);
-};
-
-#endif  // BASE_PREFS_WRITEABLE_PREF_STORE_H_