chromium/chrome/test/data/extensions/api_test/page_action/basics/update2.js

// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Test that even if we set the icon after the extension loads, it shows up.
chrome.tabs.query({active: true}, function(tabs) {
  const tab = tabs[0];
  chrome.pageAction.show(tab.id);
  chrome.pageAction.setIcon({tabId: tab.id,
      imageData:document.getElementById("canvas")
          .getContext('2d').getImageData(0, 0, 16, 16)});
  chrome.test.notifyPass();
});