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

components/prefs/pref_service.h

Index: components/prefs/pref_service.h
diff --git a/components/prefs/pref_service.h b/components/prefs/pref_service.h
index 50a827cca5bdf038da679126f97abcddcaf8fd96..7b94cb6c5cba47472f4aa45587fc03fb476aea6b 100644
--- a/components/prefs/pref_service.h
+++ b/components/prefs/pref_service.h
@@ -8,8 +8,8 @@
 // information and MUST not be extracted, overwritten or modified except
 // through Chromium defined APIs.
 
-#ifndef COMPONENTS_PREFS_PREF_SERVICE_H_
-#define COMPONENTS_PREFS_PREF_SERVICE_H_
+#ifndef BASE_PREFS_PREF_SERVICE_H_
+#define BASE_PREFS_PREF_SERVICE_H_
 
 #include <stdint.h>
 
@@ -51,7 +51,7 @@
 // Settings and storage accessed through this class represent
 // user-selected preferences and information and MUST not be
 // extracted, overwritten or modified except through the defined APIs.
-class COMPONENTS_PREFS_EXPORT PrefService : public base::NonThreadSafe {
+class BASE_PREFS_EXPORT PrefService : public base::NonThreadSafe {
  public:
   enum PrefInitializationStatus {
     INITIALIZATION_STATUS_WAITING,
@@ -61,7 +61,7 @@
   };
 
   // A helper class to store all the information associated with a preference.
-  class COMPONENTS_PREFS_EXPORT Preference {
+  class BASE_PREFS_EXPORT Preference {
    public:
     // The type of the preference is determined by the type with which it is
     // registered. This type needs to be a boolean, integer, double, string,
@@ -382,4 +382,4 @@
   DISALLOW_COPY_AND_ASSIGN(PrefService);
 };
 
-#endif  // COMPONENTS_PREFS_PREF_SERVICE_H_
+#endif  // BASE_PREFS_PREF_SERVICE_H_