Fix wrong comments about two search engine related variables

components/search_engines/default_search_manager.h

Index: components/search_engines/default_search_manager.h
diff --git a/components/search_engines/default_search_manager.h b/components/search_engines/default_search_manager.h
index e31277c96c72498b8685107d4ef26f7a28f38f79..2261d1b220addc57eb9265e19efa7923d38a0d84 100644
--- a/components/search_engines/default_search_manager.h
+++ b/components/search_engines/default_search_manager.h
@@ -146,13 +146,13 @@ class DefaultSearchManager {
   // search engine has been selected.
   scoped_ptr<TemplateURLData> fallback_default_search_;
 
-  // Default search engine provided by prefs (either user prefs or policy
-  // prefs). This will be null if no value was set in the pref store.
-  scoped_ptr<TemplateURLData> extension_default_search_;
-
   // Default search engine provided by extension (usings Settings Override API).
   // This will be null if there are no extensions installed which provide
   // default search engines.
+  scoped_ptr<TemplateURLData> extension_default_search_;
+
+  // Default search engine provided by prefs (either user prefs or policy
+  // prefs). This will be null if no value was set in the pref store.
   scoped_ptr<TemplateURLData> prefs_default_search_;
 
   // True if the default search is currently enforced by policy.