Bug 1045891 - CSPDictionary change for child-src directive r=bholley

dom/webidl/CSPDictionaries.webidl

@@ -26,6 +26,7 @@ dictionary CSP {
   sequence<DOMString> referrer;
   sequence<DOMString> manifest-src;
   sequence<DOMString> upgrade-insecure-requests;
+  sequence<DOMString> child-src;
 };
 
 dictionary CSPPolicies {