Move IsStringASCII/UTF8 to base namespace.

content/child/ftp_directory_listing_response_delegate.cc

Index: content/child/ftp_directory_listing_response_delegate.cc
diff --git a/content/child/ftp_directory_listing_response_delegate.cc b/content/child/ftp_directory_listing_response_delegate.cc
index f6bcd7c70f56f0aae6aa1cdab123881eca192494..4801e9f02d9e5a3504774fdba40a48a53e2994fd 100644
--- a/content/child/ftp_directory_listing_response_delegate.cc
+++ b/content/child/ftp_directory_listing_response_delegate.cc
@@ -34,7 +34,7 @@ namespace {
 base::string16 ConvertPathToUTF16(const std::string& path) {
   // Per RFC 2640, FTP servers should use UTF-8 or its proper subset ASCII,
   // but many old FTP servers use legacy encodings. Try UTF-8 first.
-  if (IsStringUTF8(path))
+  if (base::IsStringUTF8(path))
     return base::UTF8ToUTF16(path);
 
   // Try detecting the encoding. The sample is rather small though, so it may