diff --git a/jni/linux/ExternalWrapper.cpp b/jni/linux/ExternalWrapper.cpp
new file mode 100644
index 0000000..4f0ae72
--- /dev/null
+++ b/jni/linux/ExternalWrapper.cpp
@@ -0,0 +1,305 @@
+/*
+ * Copyright 2007 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+/*
+ * Defines the JavaScript class gwt_external_class, which interface via JNI
+ * to Java objects.
+ */
+
+#include <jni.h>
+#include "JsRootedValue.h"
+#include "gwt-jni.h"
+#include "ExternalWrapper.h"
+#include "Tracer.h"
+#include "JsStringWrap.h"
+
+// note that this does not use the NS_DEFINE_CID macro because it defines
+// the variable as const, which by default has internal linkage.  I could
+// work around it by putting extern in front of the macro, but that seems
+// fragile if the macro changes.
+nsCID kGwtExternalCID = GWT_EXTERNAL_FACTORY_CID;
+
+/*
+ * definition of JavaScript gwtOnLoad method which maps to the Java
+ * gwtOnLoad method.
+ */
+static JSBool gwtOnLoad(JSContext *cx, JSObject *obj, uintN argc,
+    jsval *argv, jsval *rval)
+{
+  Tracer tracer("gwtOnLoad");
+  if (argc < 2) {
+    tracer.setFail("less than 2 args");
+    return JS_FALSE;
+  }
+
+  JSObject* scriptWindow = 0;
+  if (argv[0] != JSVAL_NULL && argv[0] != JSVAL_VOID) {
+    if (!JS_ValueToObject(cx, argv[0], &scriptWindow)) {
+      tracer.setFail("can't get script window object");
+      return JS_FALSE;
+    }
+  }
+
+  JSString* moduleName = 0;
+  if (argv[1] != JSVAL_NULL && argv[1] != JSVAL_VOID) {
+    moduleName = JS_ValueToString(cx, argv[1]);
+  }
+
+  nsCOMPtr<nsIScriptGlobalObject> scriptGlobal(0);
+  if (scriptWindow) {
+    nsCOMPtr<nsIXPConnect> xpConnect = do_GetService(nsIXPConnect::GetCID());
+    nsCOMPtr<nsIXPConnectWrappedNative> wrappedNative;
+    xpConnect->GetWrappedNativeOfJSObject(cx, scriptWindow,
+        getter_AddRefs(wrappedNative));
+    if (wrappedNative) {
+        nsCOMPtr<nsISupports> native;
+        wrappedNative->GetNative(getter_AddRefs(native));
+        scriptGlobal = do_QueryInterface(native);
+    }
+  }
+  jstring jModuleName(0);
+  if (moduleName) {
+    jModuleName = savedJNIEnv->NewString(JS_GetStringChars(moduleName),
+        JS_GetStringLength(moduleName));
+    if (!jModuleName || savedJNIEnv->ExceptionCheck()) {
+      tracer.setFail("can't get module name in Java string");
+      return JS_FALSE;
+    }
+  }
+  
+  jobject externalObject = NS_REINTERPRET_CAST(jobject, JS_GetPrivate(cx, obj));
+  jclass objClass = savedJNIEnv->GetObjectClass(externalObject);
+  if (!objClass || savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("can't get LowLevelMoz.ExternalObject class");
+    return JS_FALSE;
+  }
+  
+  jmethodID methodID = savedJNIEnv->GetMethodID(objClass, "gwtOnLoad",
+      "(ILjava/lang/String;)Z");
+  if (!methodID || savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("can't get gwtOnLoad method");
+    return JS_FALSE;
+  }
+  
+  jboolean result = savedJNIEnv->CallBooleanMethod(externalObject, methodID,
+      NS_REINTERPRET_CAST(jint, scriptGlobal.get()), jModuleName);
+  if (savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("LowLevelMoz.ExternalObject.gwtOnLoad() threw an exception");
+    return JS_FALSE;
+  }
+  *rval = BOOLEAN_TO_JSVAL((result == JNI_FALSE) ? JS_FALSE : JS_TRUE);
+  return JS_TRUE;
+}
+
+/*=======================================================================*/
+/* Implementation of the getProperty, setProperty, and finalize methods  */
+/* for the JavaScript class gwt_external_class.                          */
+/*=======================================================================*/
+
+static JSBool JS_DLL_CALLBACK gwt_external_getProperty(JSContext *cx,
+    JSObject *obj, jsval id, jsval *vp)
+{
+  Tracer tracer("gwt_external_getProperty");
+  if (*vp != JSVAL_VOID)
+    return JS_TRUE;
+
+  if (!JSVAL_IS_STRING(id)) {
+    tracer.setFail("not a string");
+    return JS_FALSE;
+  }
+  JsStringWrap jsStr(cx, id);
+  tracer.log("obj=%08x, property=%.*s", obj, jsStr.length(), jsStr.bytes());
+
+// All this is for calling resolveReference which only returns void.  So,
+// just replace this code to return void for now.  TODO(jat): revisit when
+// merging in Toby's code. 
+#if 0
+  jstring jident = savedJNIEnv->NewString(jsStr.chars(), jsStr.length());
+  if (!jident || savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("can't create Java string ");
+    return JS_FALSE;
+  }
+  jobject externalObject = NS_REINTERPRET_CAST(jobject, JS_GetPrivate(cx, obj));
+  jclass objClass = savedJNIEnv->GetObjectClass(externalObject);
+  if (!objClass || savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("can't find Java class for JS object");
+    return JS_FALSE;
+  }
+
+  jmethodID methodID = savedJNIEnv->GetMethodID(objClass, "resolveReference",
+      "(Ljava/lang/String;)I");
+  if (!methodID || savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("exception getting method for int resolveReference(String)");
+    return JS_FALSE;
+  }
+  int retval = savedJNIEnv->CallIntMethod(externalObject, methodID, jident);
+  if (savedJNIEnv->ExceptionCheck()) {
+    tracer.setFail("exception calling int resolveReference(String)");
+    return JS_FALSE;
+  }
+  *vp = retval;
+#else
+  *vp = JSVAL_VOID;
+#endif
+  return JS_TRUE;
+}
+
+static void JS_DLL_CALLBACK gwt_external_finalize(JSContext *cx, JSObject *obj)
+{
+  jobject externalObject = NS_REINTERPRET_CAST(jobject, JS_GetPrivate(cx, obj));
+  if (externalObject)
+    savedJNIEnv->DeleteGlobalRef(externalObject);
+  JS_FinalizeStub(cx,obj);
+}
+
+static JSBool JS_DLL_CALLBACK gwt_external_setProperty(JSContext *cx,
+    JSObject *obj, jsval id, jsval *vp)
+{
+  return JS_FALSE;
+}
+ 
+static JSClass gwt_external_class = {
+    "gwt_external_class", JSCLASS_HAS_PRIVATE,
+    JS_PropertyStub, JS_PropertyStub, gwt_external_getProperty,
+    gwt_external_setProperty, JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub,
+    gwt_external_finalize,
+    JSCLASS_NO_OPTIONAL_MEMBERS
+};
+
+NS_IMPL_ISUPPORTS1(ExternalWrapper, nsIScriptObjectOwner)
+
+/*
+ * Create a new LowLevelMoz.ExternalObject instance and a JavaScript object
+ * that refers to it, mapping the gwtOnLoad member function mapping to
+ * a Javascript method.
+ */
+NS_IMETHODIMP ExternalWrapper::GetScriptObject(nsIScriptContext *aContext,
+    void** aScriptObject)
+{
+  Tracer tracer("ExternalWrapper::GetScriptObject"); 
+  if (!aScriptObject) {
+    tracer.setFail("null script object pointer");
+    return NS_ERROR_INVALID_POINTER;
+  }
+  if (!mScriptObject) {
+    *aScriptObject = 0;
+
+    nsIScriptGlobalObject* globalObject = aContext->GetGlobalObject();
+    nsCOMPtr<nsIDOMWindow> domWindow(do_QueryInterface(globalObject));
+    if (!domWindow) {
+      tracer.setFail("can't get DOM window");
+      return NS_ERROR_UNEXPECTED;
+    }
+    nsCOMPtr<nsIDOMWindow> topWindow;
+    domWindow->GetTop(getter_AddRefs(topWindow));
+    if (!topWindow) {
+      tracer.setFail("Can't get top window");
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    tracer.log("savedJNIEnv=%08x, llClass=%08x", unsigned(savedJNIEnv),
+        lowLevelMozClass);
+    
+    jmethodID methodID = savedJNIEnv->GetStaticMethodID(lowLevelMozClass,
+        "createExternalObjectForDOMWindow",
+        "(I)Lcom/google/gwt/dev/shell/moz/LowLevelMoz$ExternalObject;");
+    if (!methodID || savedJNIEnv->ExceptionCheck()) {
+      tracer.setFail("Can't get createExternalObjectForDOMWindow method");
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    jobject externalObject = savedJNIEnv->CallStaticObjectMethod(
+        lowLevelMozClass, methodID, NS_REINTERPRET_CAST(jint, topWindow.get()));
+    if (!externalObject || savedJNIEnv->ExceptionCheck()) {
+      tracer.setFail("createExternalObjectForDOMWindow failed");
+      return NS_ERROR_UNEXPECTED;
+    }
+    externalObject = savedJNIEnv->NewGlobalRef(externalObject);
+    if (!externalObject || savedJNIEnv->ExceptionCheck()) {
+      tracer.setFail("can't get GlobalRef for external object");
+      return NS_ERROR_UNEXPECTED;
+    }
+    JSContext* cx = NS_REINTERPRET_CAST(JSContext*,
+        aContext->GetNativeContext());
+    if (!cx) {
+      tracer.setFail("can't get JSContext");
+      return NS_ERROR_UNEXPECTED;
+    }
+    JSObject* newObj = JS_NewObject(cx, &gwt_external_class, 0,
+        globalObject->GetGlobalJSObject());
+    if (!newObj) {
+      tracer.setFail("can't create new gwt_external_class object");
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    if (!JS_SetPrivate(cx, newObj, externalObject)) {
+      savedJNIEnv->DeleteGlobalRef(externalObject);
+      tracer.setFail("can't store external object private reference");
+      return NS_ERROR_UNEXPECTED;
+    }
+  
+    if (!JS_DefineFunction(cx, newObj, "gwtOnLoad", gwtOnLoad, 3,
+        JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT)) {
+      tracer.setFail("can't define gwtOnLoad function on JavaScript object");
+      return NS_ERROR_UNEXPECTED;
+    }
+    mScriptObject = newObj;
+  }
+
+  *aScriptObject = mScriptObject;
+  return NS_OK;
+}
+
+NS_IMETHODIMP ExternalWrapper::SetScriptObject(void* aScriptObject)
+{
+    mScriptObject = aScriptObject;
+    return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS1(nsRpExternalFactory, nsIFactory)
+
+NS_IMETHODIMP nsRpExternalFactory::CreateInstance(nsISupports *aOuter,
+    const nsIID& aIID, void** aResult)
+{
+  Tracer tracer("nsRpExternalFactory::CreateInstance");
+  if (!aResult) {
+    tracer.setFail("null pointer for return value");
+    return NS_ERROR_INVALID_POINTER;
+  }
+  *aResult  = NULL;
+
+  if (aOuter) {
+    tracer.setFail("aOuter is not null");
+    return NS_ERROR_NO_AGGREGATION;
+  }
+
+  nsISupports* object = new ExternalWrapper();
+  if (!object) {
+    tracer.setFail("can't create a new ExternalWrapper");
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+      
+  nsresult result = object->QueryInterface(aIID, aResult);
+  if (!*aResult || NS_FAILED(result)) {
+    tracer.setFail("ExternalWrapper::QueryInterface failed");
+    delete object;
+  }
+  return result;
+}
+
+NS_IMETHODIMP nsRpExternalFactory::LockFactory(PRBool lock)
+{
+    return NS_ERROR_NOT_IMPLEMENTED;
+}