Avoid calling nsXPConnect::GetWrapperFor in the common case of wrapping a global object in its own scope. r=jst

js/src/xpconnect/src/XPCCrossOriginWrapper.cpp

@@ -406,8 +406,10 @@ WrapObject(JSContext *cx, JSObject *parent, jsval *vp, XPCWrappedNative* wn)
     }
   }
 
-  XPCWrappedNativeScope *parentScope =
-    XPCWrappedNativeScope::FindInJSObjectScope(cx, parent, nsnull, rt);
+  XPCWrappedNative *parentwn =
+    XPCWrappedNative::GetWrappedNativeOfJSObject(cx, parent);
+  NS_ASSERTION(parentwn, "parent must be a wrapped native");
+  XPCWrappedNativeScope *parentScope = parentwn->GetScope();
 
 #ifdef DEBUG_mrbkap_off
   printf("Wrapping object at %p (%s) [%p]\n",

js/src/xpconnect/src/xpcwrappednativejsops.cpp

@@ -1507,6 +1507,27 @@ XPC_WN_JSOp_ThisObject(JSContext *cx, JSObject *obj)
     AutoPopJSContext popper(threadData->GetJSContextStack());
     popper.PushIfNotTop(cx);
 
+    JSObject* outerscope = scope;
+    OBJ_TO_OUTER_OBJECT(cx, outerscope);
+    if(!outerscope)
+        return nsnull;
+
+    if(obj == outerscope)
+    {
+        // Fast-path for the common case: a window being wrapped in its own
+        // scope. Check to see if the object actually needs a XOW, and then
+        // give it one in its own scope.
+
+        if(!XPCCrossOriginWrapper::ClassNeedsXOW(obj->getClass()->name))
+            return obj;
+
+        js::AutoValueRooter tvr(cx, OBJECT_TO_JSVAL(obj));
+        if(!XPCCrossOriginWrapper::WrapObject(cx, scope, tvr.addr()))
+            return nsnull;
+
+        return JSVAL_TO_OBJECT(tvr.value());
+    }
+
     nsIScriptSecurityManager* secMan = XPCWrapper::GetSecurityManager();
     if(!secMan)
     {