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

chrome/app/client_util.cc

Index: chrome/app/client_util.cc
diff --git a/chrome/app/client_util.cc b/chrome/app/client_util.cc
index b01d86e25dd19f320897c8a0df0382de60300840..3d740a7f71cf8411cb6a45443ed5fc40369d755b 100644
--- a/chrome/app/client_util.cc
+++ b/chrome/app/client_util.cc
@@ -102,7 +102,7 @@ base::string16 GetCurrentModuleVersion() {
       FileVersionInfo::CreateFileVersionInfoForCurrentModule());
   if (file_version_info.get()) {
     base::string16 version_string(file_version_info->file_version());
-    if (Version(base::UTF16ToASCII(version_string)).IsValid())
+    if (base::Version(base::UTF16ToASCII(version_string)).IsValid())
       return version_string;
   }
   return base::string16();