Update uses of UTF conversions in content/ to use the base:: namespace.

content/browser/safe_util_win.cc

Index: content/browser/safe_util_win.cc
diff --git a/content/browser/safe_util_win.cc b/content/browser/safe_util_win.cc
index ac077f1535048fa062f65073929bda223d0d23e7..e5843fd2bca19ee8da265ac739cfd41f57601f06 100644
--- a/content/browser/safe_util_win.cc
+++ b/content/browser/safe_util_win.cc
@@ -81,7 +81,7 @@ HRESULT AVScanFile(const base::FilePath& full_path,
   // Note: SetSource looks like it needs to be called, even if empty.
   // Docs say it is optional, but it appears not calling it at all sets
   // a zone that is too restrictive.
-  hr = attachment_services->SetSource(UTF8ToWide(source_url).c_str());
+  hr = attachment_services->SetSource(base::UTF8ToWide(source_url).c_str());
   if (FAILED(hr))
     return hr;