sr=rpotts, r=gagan. 70743. switching over to new extensible URI::SchemeIs() api

content/base/src/nsXMLHttpRequest.cpp

@@ -860,7 +860,7 @@ nsXMLHttpRequest::OpenRequest(const char *method,
   // The following check takes the place of nsScriptSecurityManager::CheckLoadURI
   // since loads of http URLs are always allowed.
   PRBool isHTTP = PR_FALSE;
-  uri->SchemeIs(nsIURI::HTTP, &isHTTP);
+  uri->SchemeIs("http", &isHTTP);
   if (!isHTTP)
       return NS_ERROR_INVALID_ARG;