feat(script): implement some of the non-ordinary internal methods of `Location`

<https://html.spec.whatwg.org/multipage/#the-location-interface>

 - `[[GetPrototypeOf]]`: not yet
 - `[[SetPrototypeOf]]`: not yet
 - `[[IsExtensible]]`: `proxyhandler::is_extensible`
 - `[[PreventExtensions]]`: `proxyhandler::prevent_extensions`
 - `[[GetOwnProperty]]`: `CGDOMJSProxyHandler_getOwnPropertyDescriptor` (updated)
 - `[[DefineOwnProperty]]`: `CGDOMJSProxyHandler_defineProperty` (updated)
 - `[[Get]]`: `CGDOMJSProxyHandler_get` (updated)
 - `[[Set]]`: not yet
 - `[[Delete]]`: `CGDOMJSProxyHandler_delete` (updated)
 - `[[OwnPropertyKeys]]`: `CGDOMJSProxyHandler_ownPropertyKeys` (updated)

1 files changed, 8 insertions, 0 deletions

diff --git a/components/script/dom/bindings/codegen/Configuration.py b/components/script/dom/bindings/codegen/Configuration.py
index b92f68af3b9..cf6885be265 100644
--- a/components/script/dom/bindings/codegen/Configuration.py
+++ b/components/script/dom/bindings/codegen/Configuration.py
@@ -299,6 +299,9 @@ class Descriptor(DescriptorProvider):
                 if iface:
                     iface.setUserData('hasConcreteDescendant', True)
 
+            if self.isMaybeCrossOriginObject():
+                self.proxy = True
+
             if self.proxy:
                 iface = self.interface
                 while iface.parent:
@@ -404,6 +407,11 @@ class Descriptor(DescriptorProvider):
     def supportsIndexedProperties(self):
         return self.operations['IndexedGetter'] is not None
 
+    def isMaybeCrossOriginObject(self):
+        # If we're isGlobal and have cross-origin members, we're a Window, and
+        # that's not a cross-origin object.  The WindowProxy is.
+        return self.concrete and self.interface.hasCrossOriginMembers and not self.isGlobal()
+
     def hasDescendants(self):
         return (self.interface.getUserData("hasConcreteDescendant", False)
                 or self.interface.getUserData("hasProxyDescendant", False))