Bug 1104955 part 3. Pass our unscopable names to CreateInterfaceObjects and have it define the right thing on the prototype. r=khuey

dom/bindings/BindingUtils.cpp

@@ -766,7 +766,8 @@ CreateInterfacePrototypeObject(JSContext* cx, JS::Handle<JSObject*> global,
                                JS::Handle<JSObject*> parentProto,
                                const js::Class* protoClass,
                                const NativeProperties* properties,
-                               const NativeProperties* chromeOnlyProperties)
+                               const NativeProperties* chromeOnlyProperties,
+                               const char* const* unscopableNames)
 {
   JS::Rooted<JSObject*> ourProto(cx,
     JS_NewObjectWithUniqueType(cx, Jsvalify(protoClass), parentProto));
@@ -775,6 +776,28 @@ CreateInterfacePrototypeObject(JSContext* cx, JS::Handle<JSObject*> global,
     return nullptr;
   }
 
+  if (unscopableNames) {
+    JS::Rooted<JSObject*> unscopableObj(cx, JS_NewPlainObject(cx));
+    if (!unscopableObj) {
+      return nullptr;
+    }
+
+    for (; *unscopableNames; ++unscopableNames) {
+      if (!JS_DefineProperty(cx, unscopableObj, *unscopableNames,
+                             JS::TrueHandleValue, JSPROP_ENUMERATE)) {
+        return nullptr;
+      }
+    }
+
+    JS::Rooted<jsid> unscopableId(cx,
+      SYMBOL_TO_JSID(JS::GetWellKnownSymbol(cx, JS::SymbolCode::unscopables)));
+    // Readonly and non-enumerable to match Array.prototype.
+    if (!JS_DefinePropertyById(cx, ourProto, unscopableId, unscopableObj,
+                               JSPROP_READONLY)) {
+      return nullptr;
+    }
+  }
+
   return ourProto;
 }
 
@@ -830,7 +853,8 @@ CreateInterfaceObjects(JSContext* cx, JS::Handle<JSObject*> global,
                        JS::Heap<JSObject*>* constructorCache,
                        const NativeProperties* properties,
                        const NativeProperties* chromeOnlyProperties,
-                       const char* name, bool defineOnGlobal)
+                       const char* name, bool defineOnGlobal,
+                       const char* const* unscopableNames)
 {
   MOZ_ASSERT(protoClass || constructorClass || constructor,
              "Need at least one class or a constructor!");
@@ -861,7 +885,8 @@ CreateInterfaceObjects(JSContext* cx, JS::Handle<JSObject*> global,
   if (protoClass) {
     proto =
       CreateInterfacePrototypeObject(cx, global, protoProto, protoClass,
-                                     properties, chromeOnlyProperties);
+                                     properties, chromeOnlyProperties,
+                                     unscopableNames);
     if (!proto) {
       return;
     }

dom/bindings/BindingUtils.h

@@ -594,6 +594,8 @@ struct NamedConstructor
  *                false in situations where we want the properties to only
  *                appear on privileged Xrays but not on the unprivileged
  *                underlying global.
+ * unscopableNames if not null it points to a null-terminated list of const
+ *                 char* names of the unscopable properties for this interface.
  *
  * At least one of protoClass, constructorClass or constructor should be
  * non-null. If constructorClass or constructor are non-null, the resulting
@@ -610,7 +612,8 @@ CreateInterfaceObjects(JSContext* cx, JS::Handle<JSObject*> global,
                        JS::Heap<JSObject*>* constructorCache,
                        const NativeProperties* regularProperties,
                        const NativeProperties* chromeOnlyProperties,
-                       const char* name, bool defineOnGlobal);
+                       const char* name, bool defineOnGlobal,
+                       const char* const* unscopableNames);
 
 /**
  * Define the properties (regular and chrome-only) on obj.

dom/bindings/Codegen.py

@@ -2745,13 +2745,14 @@ class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
 
     properties should be a PropertyArrays instance.
     """
-    def __init__(self, descriptor, properties):
+    def __init__(self, descriptor, properties, haveUnscopables):
         args = [Argument('JSContext*', 'aCx'),
                 Argument('JS::Handle<JSObject*>', 'aGlobal'),
                 Argument('ProtoAndIfaceCache&', 'aProtoAndIfaceCache'),
                 Argument('bool', 'aDefineOnGlobal')]
         CGAbstractMethod.__init__(self, descriptor, 'CreateInterfaceObjects', 'void', args)
         self.properties = properties
+        self.haveUnscopables = haveUnscopables
 
     def definition_body(self):
         (protoGetter, protoHandleGetter) = InterfacePrototypeObjectProtoGetter(self.descriptor)
@@ -2891,7 +2892,8 @@ class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
                                         interfaceCache,
                                         ${properties},
                                         ${chromeProperties},
-                                        ${name}, aDefineOnGlobal);
+                                        ${name}, aDefineOnGlobal,
+                                        ${unscopableNames});
             """,
             protoClass=protoClass,
             parentProto=parentProto,
@@ -2903,7 +2905,8 @@ class CGCreateInterfaceObjectsMethod(CGAbstractMethod):
             interfaceCache=interfaceCache,
             properties=properties,
             chromeProperties=chromeProperties,
-            name='"' + self.descriptor.interface.identifier.name + '"' if needInterfaceObject else "nullptr")
+            name='"' + self.descriptor.interface.identifier.name + '"' if needInterfaceObject else "nullptr",
+            unscopableNames="unscopableNames" if self.haveUnscopables else "nullptr")
 
         # If we fail after here, we must clear interface and prototype caches
         # using this code: intermediate failure must not expose the interface in
@@ -12078,7 +12081,8 @@ class CGDescriptor(CGThing):
 
         # CGCreateInterfaceObjectsMethod needs to come after our
         # CGDOMJSClass and unscopables, if any.
-        cgThings.append(CGCreateInterfaceObjectsMethod(descriptor, properties))
+        cgThings.append(CGCreateInterfaceObjectsMethod(descriptor, properties,
+                                                       haveUnscopables))
 
         # CGGetProtoObjectMethod and CGGetConstructorObjectMethod need
         # to come after CGCreateInterfaceObjectsMethod.

testing/web-platform/meta/MANIFEST.json

@@ -34873,6 +34873,12 @@
             "url": "/dom/collections/HTMLCollection-as-proto-length-get-throws.html"
           }
         ],
+        "dom/nodes/remove-unscopable.html": [
+          {
+            "path": "dom/nodes/remove-unscopable.html",
+            "url": "/dom/nodes/remove-unscopable.html"
+          }
+        ],
         "js/builtins/Promise-incumbent-global.sub.html": [
           {
             "path": "js/builtins/Promise-incumbent-global.sub.html",

testing/web-platform/tests/dom/nodes/remove-unscopable.html

@@ -0,0 +1,18 @@
+<!doctype html>
+<meta charset=utf-8>
+<title></title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<div id="testDiv" onclick="result1 = remove; result2 = this.remove;"></div>
+<script>
+var remove = "Hello there";
+var result1;
+var result2;
+test(function() {
+  assert_true(Element.prototype[Symbol.unscopables].remove);
+  var div = document.querySelector("#testDiv");
+  div.dispatchEvent(new Event("click"));
+  assert_equals(typeof result1, "string");
+  assert_equals(typeof result2, "function");
+}, "remove() should be unscopable")
+</script>