Revert of Move base/prefs to components/prefs

base/prefs/writeable_pref_store.h

Index: base/prefs/writeable_pref_store.h
diff --git a/base/prefs/writeable_pref_store.h b/base/prefs/writeable_pref_store.h
index 69bd2cbf290859bb1bbbf77f7df867c23599ab3a..f7da279ac02ee9f543dae61eb1fcb6b3c0d17fc8 100644
--- a/base/prefs/writeable_pref_store.h
+++ b/base/prefs/writeable_pref_store.h
@@ -2,6 +2,71 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(brettw) remove this forwarding header when prefs is completely moved to
-// components.
-#include "components/prefs/writeable_pref_store.h"
+#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_