Bug 1157898 part 1. Make code of the form "return rv.ErrorCode();" where rv is an ErrorResult use StealNSResult instead. r=peterv

This patch was generated with the following command:

  find . -name "*.h" -o -name "*.cpp" | xargs perl -pi -e 's/return ([a-zA-Z0-9]+)\.ErrorCode\(\);/return \1.StealNSResult();/'

dom/html/HTMLFormElement.cpp

@@ -270,7 +270,7 @@ HTMLFormElement::Submit()
 {
   ErrorResult rv;
   Submit(rv);
-  return rv.ErrorCode();
+  return rv.StealNSResult();
 }
 
 NS_IMETHODIMP