Move IsStringASCII/UTF8 to base namespace.

chrome/common/extensions/manifest_handlers/content_scripts_handler.cc

Index: chrome/common/extensions/manifest_handlers/content_scripts_handler.cc
diff --git a/chrome/common/extensions/manifest_handlers/content_scripts_handler.cc b/chrome/common/extensions/manifest_handlers/content_scripts_handler.cc
index 2753614d523e78fa55ff29da77a7d02dba4a6e56..9a699b2013259706083215fc04001ae426754493 100644
--- a/chrome/common/extensions/manifest_handlers/content_scripts_handler.cc
+++ b/chrome/common/extensions/manifest_handlers/content_scripts_handler.cc
@@ -304,7 +304,7 @@ static bool IsScriptValid(const base::FilePath& path,
     return false;
   }
 
-  if (!IsStringUTF8(content)) {
+  if (!base::IsStringUTF8(content)) {
     *error = l10n_util::GetStringFUTF8(
         IDS_EXTENSION_BAD_FILE_ENCODING,
         relative_path.LossyDisplayName());