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

components/prefs/json_pref_store.h

Index: components/prefs/json_pref_store.h
diff --git a/components/prefs/json_pref_store.h b/components/prefs/json_pref_store.h
index 4b19c95d588f796804506665918ba26ed4006447..30c1642a77fa938cb6631448fa86103e5d605680 100644
--- a/components/prefs/json_pref_store.h
+++ b/components/prefs/json_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_JSON_PREF_STORE_H_
-#define COMPONENTS_PREFS_JSON_PREF_STORE_H_
+#ifndef BASE_PREFS_JSON_PREF_STORE_H_
+#define BASE_PREFS_JSON_PREF_STORE_H_
 
 #include <stdint.h>
 
@@ -41,7 +41,7 @@
 }
 
 // A writable PrefStore implementation that is used for user preferences.
-class COMPONENTS_PREFS_EXPORT JsonPrefStore
+class BASE_PREFS_EXPORT JsonPrefStore
     : public PersistentPrefStore,
       public base::ImportantFileWriter::DataSerializer,
       public base::SupportsWeakPtr<JsonPrefStore>,
@@ -114,7 +114,7 @@
  private:
   // Represents a histogram for recording the number of writes to the pref file
   // that occur every kHistogramWriteReportIntervalInMins minutes.
-  class COMPONENTS_PREFS_EXPORT WriteCountHistogram {
+  class BASE_PREFS_EXPORT WriteCountHistogram {
    public:
     static const int32_t kHistogramWriteReportIntervalMins;
 
@@ -226,4 +226,4 @@
   DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
 };
 
-#endif  // COMPONENTS_PREFS_JSON_PREF_STORE_H_
+#endif  // BASE_PREFS_JSON_PREF_STORE_H_