Bug 860473 part 1. Root WebIDL dictionary ParseJSON. r=evilpie, smaug

dom/bindings/BindingDeclarations.h

@@ -34,9 +34,9 @@ struct MainThreadDictionaryBase
 {
 protected:
   JSContext* ParseJSON(const nsAString& aJSON,
-                       mozilla::Maybe<JSAutoRequest>& aAr,
-                       mozilla::Maybe<JSAutoCompartment>& aAc,
-                       JS::Value& aVal);
+                       Maybe<JSAutoRequest>& aAr,
+                       Maybe<JSAutoCompartment>& aAc,
+                       Maybe< JS::Rooted<JS::Value> >& aVal);
 };
 
 struct EnumEntry {

dom/bindings/BindingUtils.cpp

@@ -1307,21 +1307,22 @@ SetXrayExpandoChain(JSObject* obj, JSObject* chain)
 
 JSContext*
 MainThreadDictionaryBase::ParseJSON(const nsAString& aJSON,
-                                    mozilla::Maybe<JSAutoRequest>& aAr,
-                                    mozilla::Maybe<JSAutoCompartment>& aAc,
-                                    JS::Value& aVal)
+                                    Maybe<JSAutoRequest>& aAr,
+                                    Maybe<JSAutoCompartment>& aAc,
+                                    Maybe< JS::Rooted<JS::Value> >& aVal)
 {
   JSContext* cx = nsContentUtils::ThreadJSContextStack()->GetSafeJSContext();
   NS_ENSURE_TRUE(cx, nullptr);
   JSObject* global = JS_GetGlobalObject(cx);
   aAr.construct(cx);
   aAc.construct(cx, global);
+  aVal.construct(cx, JS::UndefinedValue());
   if (aJSON.IsEmpty()) {
     return cx;
   }
   if (!JS_ParseJSON(cx,
                     static_cast<const jschar*>(PromiseFlatString(aJSON).get()),
-                    aJSON.Length(), &aVal)) {
+                    aJSON.Length(), aVal.ref().address())) {
     return nullptr;
   }
   return cx;

dom/bindings/Codegen.py

@@ -6817,12 +6817,12 @@ class CGDictionary(CGThing):
                 "\n" +
                 ("  bool Init(const nsAString& aJSON)\n"
                  "  {\n"
-                 "    mozilla::Maybe<JSAutoRequest> ar;\n"
-                 "    mozilla::Maybe<JSAutoCompartment> ac;\n"
-                 "    jsval json = JSVAL_VOID;\n"
+                 "    Maybe<JSAutoRequest> ar;\n"
+                 "    Maybe<JSAutoCompartment> ac;\n"
+                 "    Maybe< JS::Rooted<JS::Value> > json;\n"
                  "    JSContext* cx = ParseJSON(aJSON, ar, ac, json);\n"
                  "    NS_ENSURE_TRUE(cx, false);\n"
-                 "    return Init(cx, nullptr, json);\n"
+                 "    return Init(cx, nullptr, json.ref());\n"
                  "  }\n" if not self.workers else "") +
                 "\n" +
                 "\n".join(memberDecls) + "\n"