Bug 1479712 part 5 - Use JSAutoRealm instead of JSAutoRealmAllowCCW in xpc::StackScopedClone. r=bholley

js/xpconnect/src/ExportHelpers.cpp

@@ -206,20 +206,13 @@ public:
  * function returns, |val| is set to the result of the clone.
  */
 bool
-StackScopedClone(JSContext* cx, StackScopedCloneOptions& options,
+StackScopedClone(JSContext* cx, StackScopedCloneOptions& options, HandleObject sourceScope,
                  MutableHandleValue val)
 {
     StackScopedCloneData data(cx, &options);
     {
-        // For parsing val we have to enter its realm.
-        // (unless it's a primitive)
-        Maybe<JSAutoRealmAllowCCW> ar;
-        if (val.isObject()) {
-            ar.emplace(cx, &val.toObject());
-        } else if (val.isString() && !JS_WrapValue(cx, val)) {
-            return false;
-        }
-
+        // For parsing val we have to enter (a realm in) its compartment.
+        JSAutoRealm ar(cx, sourceScope);
         if (!data.Write(cx, val))
             return false;
     }

js/xpconnect/src/XPCComponents.cpp

@@ -2967,10 +2967,13 @@ xpc::CloneInto(JSContext* aCx, HandleValue aValue, HandleValue aScope,
     if (aOptions.isObject() && !options.Parse())
         return false;
 
+    js::AssertSameCompartment(aCx, aValue);
+    RootedObject sourceScope(aCx, JS::CurrentGlobalOrNull(aCx));
+
     {
         JSAutoRealm ar(aCx, scope);
         aCloned.set(aValue);
-        if (!StackScopedClone(aCx, options, aCloned))
+        if (!StackScopedClone(aCx, options, sourceScope, aCloned))
             return false;
     }
 

js/xpconnect/src/xpcprivate.h

@@ -2806,7 +2806,8 @@ CloneInto(JSContext* cx, JS::HandleValue vobj, JS::HandleValue vscope,
           JS::HandleValue voptions, JS::MutableHandleValue rval);
 
 bool
-StackScopedClone(JSContext* cx, StackScopedCloneOptions& options, JS::MutableHandleValue val);
+StackScopedClone(JSContext* cx, StackScopedCloneOptions& options, JS::HandleObject sourceScope,
+                 JS::MutableHandleValue val);
 
 } /* namespace xpc */