Add utf_string_conversions to base namespace.

chrome/browser/ui/webui/fileicon_source.cc

Index: chrome/browser/ui/webui/fileicon_source.cc
diff --git a/chrome/browser/ui/webui/fileicon_source.cc b/chrome/browser/ui/webui/fileicon_source.cc
index b0d46097709dc5db8ecc2296a82116e6f66ce1d1..81b80502baf129bc3ba15bb1eae875d663cfc067 100644
--- a/chrome/browser/ui/webui/fileicon_source.cc
+++ b/chrome/browser/ui/webui/fileicon_source.cc
@@ -52,7 +52,7 @@ void GetFilePathAndQuery(const std::string& url,
   // The path we receive has the wrong slashes and escaping for what we need;
   // this only appears to matter for getting icons from .exe files.
   std::replace(path.begin(), path.end(), '/', '\\');
-  *file_path = base::FilePath(UTF8ToWide(path));
+  *file_path = base::FilePath(base::UTF8ToWide(path));
 #elif defined(OS_POSIX)
   // The correct encoding on Linux may not actually be UTF8.
   *file_path = base::FilePath(path);