Revert of Delete base/prefs and update callers to use components.

components/prefs/writeable_pref_store.h

Index: components/prefs/writeable_pref_store.h
diff --git a/components/prefs/writeable_pref_store.h b/components/prefs/writeable_pref_store.h
index 0cb9f83d7b36042e30051fb2b7e34e8c7dbc595e..94754d389ce0be2310c2f9eb118abe93eb115064 100644
--- a/components/prefs/writeable_pref_store.h
+++ b/components/prefs/writeable_pref_store.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_PREFS_WRITEABLE_PREF_STORE_H_
-#define COMPONENTS_PREFS_WRITEABLE_PREF_STORE_H_
+#ifndef BASE_PREFS_WRITEABLE_PREF_STORE_H_
+#define BASE_PREFS_WRITEABLE_PREF_STORE_H_
 
 #include <stdint.h>
 
@@ -18,7 +18,7 @@
 }
 
 // A pref store that can be written to as well as read from.
-class COMPONENTS_PREFS_EXPORT WriteablePrefStore : public PrefStore {
+class BASE_PREFS_EXPORT WriteablePrefStore : public PrefStore {
  public:
   // PrefWriteFlags can be used to change the way a pref will be written to
   // storage.
@@ -69,4 +69,4 @@
   DISALLOW_COPY_AND_ASSIGN(WriteablePrefStore);
 };
 
-#endif  // COMPONENTS_PREFS_WRITEABLE_PREF_STORE_H_
+#endif  // BASE_PREFS_WRITEABLE_PREF_STORE_H_