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

content/child/npapi/webplugin_delegate_impl_win.cc

Index: content/child/npapi/webplugin_delegate_impl_win.cc
diff --git a/content/child/npapi/webplugin_delegate_impl_win.cc b/content/child/npapi/webplugin_delegate_impl_win.cc
index d64af01c4fdb989cbb2ff0049d7983a3bedfeae9..468ca188c166516e34d48f385d1bd39ec444a629 100644
--- a/content/child/npapi/webplugin_delegate_impl_win.cc
+++ b/content/child/npapi/webplugin_delegate_impl_win.cc
@@ -187,7 +187,7 @@ std::wstring GetKeyPath(HKEY key) {
 }
 
 uint32_t GetPluginMajorVersion(const WebPluginInfo& plugin_info) {
-  Version plugin_version;
+  base::Version plugin_version;
   WebPluginInfo::CreateVersionFromString(plugin_info.version, &plugin_version);
 
   uint32_t major_version = 0;