Add test for sending webContents instance over IPC

spec/api-ipc-spec.js

@@ -327,6 +327,15 @@ describe('ipc module', function () {
       ipcRenderer.send('message', document.location)
     })
 
+    it('can send Electron API objects', function (done) {
+      const webContents = remote.getCurrentWebContents()
+      ipcRenderer.once('message', function (event, value) {
+        assert.deepEqual(value.browserWindowOptions, webContents.browserWindowOptions)
+        done()
+       })
+      ipcRenderer.send('message', webContents)
+    })
+
     it('does not crash on HTTP request objects (regression)', function (done) {
       const request = http.request({port: 5000, hostname: '127.0.0.1', method: 'GET', path: '/'})
       request.on('error', function () {})