Change XBL constructor/destructor back to having "this" in the scope chain like

they did when they were event handlers (to avoid breaking bindings where people
forgot to use "this" in the constructor or destructor).  Bug 258833, r=bryner,
sr=jst

content/xbl/src/nsXBLProtoImplMethod.cpp

@@ -47,7 +47,7 @@
 #include "nsReadableUtils.h"
 #include "nsXBLProtoImplMethod.h"
 #include "nsIScriptContext.h"
-#include "nsIXPConnect.h"
+#include "nsContentUtils.h"
 
 MOZ_DECL_CTOR_COUNTER(nsXBLProtoImplMethod)
 
@@ -256,25 +256,27 @@ nsXBLProtoImplAnonymousMethod::Execute(nsIContent* aBoundElement)
 
   JSObject* globalObject = ::JS_GetGlobalObject(cx);
 
-  JSObject* method = ::JS_CloneFunctionObject(cx, mJSMethodObject,
-                                              globalObject);
-  if (!method) {
-    return NS_ERROR_OUT_OF_MEMORY;
-  }
-
-  nsresult rv;
-  nsCOMPtr<nsIXPConnect> xpc(do_GetService(nsIXPConnect::GetCID(), &rv));
-  NS_ENSURE_SUCCESS(rv, rv);
-
   nsCOMPtr<nsIXPConnectJSObjectHolder> wrapper;
-  rv = xpc->WrapNative(cx, globalObject, aBoundElement,
-                       NS_GET_IID(nsISupports), getter_AddRefs(wrapper));
+  nsresult rv =
+    nsContentUtils::XPConnect()->WrapNative(cx, globalObject,
+                                            aBoundElement,
+                                            NS_GET_IID(nsISupports),
+                                            getter_AddRefs(wrapper));
   NS_ENSURE_SUCCESS(rv, rv);
 
   JSObject* thisObject;
   rv = wrapper->GetJSObject(&thisObject);
   NS_ENSURE_SUCCESS(rv, rv);
 
+  // Clone the function object, using thisObject as the parent so "this" is in
+  // the scope chain of the resulting function (for backwards compat to the
+  // days when this was an event handler).
+  JSObject* method = ::JS_CloneFunctionObject(cx, mJSMethodObject,
+                                              thisObject);
+  if (!method) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
   // Now call the method
   jsval retval;
   if (!::JS_CallFunctionValue(cx, thisObject, OBJECT_TO_JSVAL(method),