Update some uses of char16 to use the base:: namespace.

content/browser/webui/web_ui_impl.cc

Index: content/browser/webui/web_ui_impl.cc
diff --git a/content/browser/webui/web_ui_impl.cc b/content/browser/webui/web_ui_impl.cc
index 0c54523d138e547bb64acac2b620fed201d306f3..a4c996cc9418350d40a6a5b9f2a7de2641c99a22 100644
--- a/content/browser/webui/web_ui_impl.cc
+++ b/content/browser/webui/web_ui_impl.cc
@@ -34,13 +34,13 @@ base::string16 WebUI::GetJavascriptCall(
   std::string json;
   for (size_t i = 0; i < arg_list.size(); ++i) {
     if (i > 0)
-      parameters += char16(',');
+      parameters += base::char16(',');
 
     base::JSONWriter::Write(arg_list[i], &json);
     parameters += base::UTF8ToUTF16(json);
   }
   return base::ASCIIToUTF16(function_name) +
-      char16('(') + parameters + char16(')') + char16(';');
+      base::char16('(') + parameters + base::char16(')') + base::char16(';');
 }
 
 WebUIImpl::WebUIImpl(WebContents* contents)