Add header validation in update response algorithm

Author: juliandescottes

index.bs

@@ -4751,7 +4751,17 @@ To <dfn>update the response</dfn> given |session|, |command| and |command parame
 
   1. For |header| in |command parameters|["<code>headers</code>"]:
 
-    1. Append [=deserialize header=] with |header| to |headers|.
+    1. Let |deserialized header| be [=deserialize header=] with |header|.
+
+    1. If |deserialized header|'s name does not match the [=field-name token=]
+       production, return [=error=] with [=error code=]
+      "<code>invalid argument</code>".
+
+    1. If |deserialized header|'s value does not match the [=header value=]
+       production, return [=error=] with [=error code=]
+      "<code>invalid argument</code>".
+
+    1. Append |deserialized header| to |headers|.
 
   1. Set |response|'s [=response/header list=] to |headers|.