Special-case LocalDOMWindow for same-origin access in bindings.

third_party/WebKit/Source/bindings/templates/attributes.cpp.tmpl

 {% from 'utilities.cpp.tmpl' import declare_enum_validation_variable, v8_value_to_local_cpp_value %}
 
 {##############################################################################}
 {% macro attribute_getter(attribute, world_suffix) %}
 static void {{attribute.name}}AttributeGetter{{world_suffix}}(
 {%- if attribute.is_data_type_property %}
 const v8::PropertyCallbackInfo<v8::Value>& info
 {%- else %}
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- endif %}) {
@@ skipping 25 matching lines @@
   {
     v8::Local<v8::Value> v8Value = privateSameObject.get(info.GetIsolate()->GetCurrentContext(), holder);
     if (!v8Value.IsEmpty()) {
       v8SetReturnValue(info, v8Value);
       return;
     }
   }
   {% endif %}
 
   {% if not attribute.is_static %}
+  {% if interface_name == 'Window' and not attribute.has_cross_origin_getter %}
+  // Same-origin attribute getters are never exposed via the cross-origin
+  // interceptors. Since same-origin access requires a LocalDOMWindow, it is
+  // safe to downcast here.
+  LocalDOMWindow* impl = toLocalDOMWindow({{v8_class}}::toImpl(holder));
+  {% else %}
   {{cpp_class}}* impl = {{v8_class}}::toImpl(holder);
   {% endif %}
+  {% endif %}
 
   {% if attribute.cached_attribute_validation_method %}
   // [CachedAttribute]
   v8::Local<v8::String> propertyName = v8AtomicString(info.GetIsolate(), "{{attribute.name}}");
   if (!impl->{{attribute.cached_attribute_validation_method}}()) {
     v8::Local<v8::Value> v8Value = V8HiddenValue::getHiddenValue(ScriptState::forFunctionObject(info), holder, propertyName);
     if (!v8Value.IsEmpty() && !v8Value->IsUndefined()) {
       v8SetReturnValue(info, v8Value);
       return;
     }
@@ skipping 217 matching lines @@
   {% endif %}
 
   {% if not attribute.is_static and not attribute.is_replaceable %}
   v8::Local<v8::Object> holder = info.Holder();
   {% if attribute.is_put_forwards %}
   {{cpp_class}}* proxyImpl = {{v8_class}}::toImpl(holder);
   {{attribute.cpp_type}} impl = WTF::getPtr(proxyImpl->{{attribute.name}}());
   if (!impl)
     return;
   {% else %}
+  {% if interface_name == 'Window' and not attribute.has_cross_origin_setter %}
+  // Same-origin attribute setters are never exposed via the cross-origin
+  // interceptors. Since same-origin access requires a LocalDOMWindow, it is
+  // safe to downcast here.
+  LocalDOMWindow* impl = toLocalDOMWindow({{v8_class}}::toImpl(holder));
+  {% else %}
   {{cpp_class}}* impl = {{v8_class}}::toImpl(holder);
   {% endif %}
   {% endif %}
+  {% endif %}
 
   {% if attribute.is_check_security_for_receiver and not attribute.is_data_type_property %}
   // Perform a security check for the receiver object.
   {{define_exception_state}}
   if (!BindingSecurity::shouldAllowAccessTo(currentDOMWindow(info.GetIsolate()), impl, exceptionState)) {
     v8SetReturnValue(info, v8Value);
     return;
   }
   {% endif %}
 
@@ skipping 161 matching lines @@
        getter_callback_for_main_world,
        setter_callback_for_main_world,
        cached_accessor_callback,
        wrapper_type_info,
        property_attribute,
        property_location(attribute),
        holder_check,
    ] %}
 {{'{'}}{{attribute_configuration_list | join(', ')}}{{'}'}}
 {%- endmacro %}