Injecting a script into a page using Atom-Shell

gistfile1.js

app.on('ready', function() {
    var injectscript = escape(__dirname + '/inject/test.js');
    mainWindow = new BrowserWindow( { width: '800px', height: '600px', 'web-preferences': { 'web-security': false } });
    mainWindow.loadUrl('http://google.com' );
    mainWindow.openDevTools();
    mainWindow.getWebContents().on('did-finish-load', function() {
        var remotejs = "var js = document.createElement('script'); \
                        js.src = 'file://' + unescape('" + injectscript + "'); \
                        console.log(js); \
                        document.getElementsByTagName('body')[0].appendChild(js);";

        this.executeJavaScript(remotejs);
    });
}