Add failing spec for chrome.runtime.id

spec/api-browser-window-spec.js

@@ -863,7 +863,7 @@ describe('browser-window module', function () {
           w.webContents.openDevTools({mode: 'bottom'})
 
           ipcMain.once('answer', function (event, message) {
-            assert.equal(message, 'extension loaded')
+            assert.equal(message.runtimeId, 'foo')
             done()
           })
         })
@@ -873,8 +873,8 @@ describe('browser-window module', function () {
         it('creates the extension', function (done) {
           w.webContents.openDevTools({mode: 'undocked'})
 
-          ipcMain.once('answer', function (event, message) {
-            assert.equal(message, 'extension loaded')
+          ipcMain.once('answer', function (event, message, extensionId) {
+            assert.equal(message.runtimeId, 'foo')
             done()
           })
         })

spec/fixtures/devtools-extensions/foo/index.html

@@ -4,7 +4,10 @@
     <meta charset="utf-8">
     <title></title>
     <script>
-      var sendMessage = `require('electron').ipcRenderer.send('answer', 'extension loaded')`
+      var message = JSON.stringify({
+        runtimeId: chrome.runtime.id
+      })
+      var sendMessage = `require('electron').ipcRenderer.send('answer', ${message})`
       window.chrome.devtools.inspectedWindow.eval(sendMessage, function () {})
     </script>
   </head>