base: Remove using:: declaration from version.h header.

chrome/browser/extensions/extension_sync_data.h

Index: chrome/browser/extensions/extension_sync_data.h
diff --git a/chrome/browser/extensions/extension_sync_data.h b/chrome/browser/extensions/extension_sync_data.h
index 2c753f3955e46bb31276e305eca4173da3d2ab41..d2d7342619610d7f1d0ca45464dffc6a2309472b 100644
--- a/chrome/browser/extensions/extension_sync_data.h
+++ b/chrome/browser/extensions/extension_sync_data.h
@@ -96,7 +96,7 @@ class ExtensionSyncData {
 
   // Version-dependent properties (i.e., should be used only when the
   // version of the currently-installed extension matches |version|).
-  const Version& version() const { return version_; }
+  const base::Version& version() const { return version_; }
   const GURL& update_url() const { return update_url_; }
   // Used only for debugging.
   const std::string& name() const { return name_; }
@@ -154,7 +154,7 @@ class ExtensionSyncData {
   bool remote_install_;
   OptionalBoolean all_urls_enabled_;
   bool installed_by_custodian_;
-  Version version_;
+  base::Version version_;
   GURL update_url_;
   std::string name_;