Continue key propagation for extensions without any listeners to chrome.commands.onCommand.

chrome/test/data/extensions/api_test/keybinding/continue_propagation/background.js

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var stage = 'DOM';

[Finnur, 2014/08/28 11:15:39]

Add:
// Keeps track of who should be receiving keystrokes sent: 
// The web page (DOM) or the background page (onCommand).

And perhaps consider using more descriptive names.

Pseudo code:   expectedListener = [ "WebPage" | "BackgroundPage" ]

[David Tseng, 2014/08/28 23:37:11]

Done.

+
+function gotCommand(command) {
+  if (stage == 'onCommand') {
+    stage = 'DOM';
+    chrome.commands.onCommand.removeListener(gotCommand);
+    chrome.test.notifyPass();
+  } else {
+    chrome.test.notifyFail('Unexpected call to onCommand');

[Finnur, 2014/08/28 11:15:39]

nit: Change error to something like:
'Webpage expecting keystroke, but sent to extension instead'.

[David Tseng, 2014/08/28 23:37:11]

Done.

+  }
+}
+
+chrome.extension.onConnect.addListener(function(port) {
+  port.onMessage.addListener(function(message) {
+    if (stage == 'DOM') {
+      stage = 'onCommand';
+      chrome.commands.onCommand.addListener(gotCommand);
+      chrome.test.notifyPass();
+    } else {
+      chrome.test.notifyFail('Unexpected key event on page');

[Finnur, 2014/08/28 11:15:39]

nit: Change error to something like:
'Extension expecting keystroke, but sent to webpage instead'.

+    }
+  });
+}    );

[Finnur, 2014/08/28 11:15:39]

nit: Extra spaces.

+
+chrome.test.notifyPass();