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

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

Index: third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
diff --git a/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl b/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
index 43137dc9d98225944e18cfdd1fce805d56ffb8ed..91b400d223096f28298c027e5bb419db78bb0a46 100644
--- a/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
+++ b/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
@@ -29,8 +29,15 @@ static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const
     return;
   }
   {% endif %}
+  {% if interface_name == 'Window' and not method.is_cross_origin %}
+  // Same-origin methods 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(info.Holder()));
+  {% else %}
   {{cpp_class}}* impl = {{v8_class}}::toImpl(info.Holder());
   {% endif %}
+  {% endif %}
 
   {# Security checks #}
   {% if method.is_check_security_for_receiver %}