Make some updates to extension iconography.

chrome/test/data/extensions/context_menus/icons/sample.js

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.

[Devlin, 2016/12/15 17:14:41]

not 2010

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+

[Devlin, 2016/12/15 17:14:41]

I just realized this whole file was copy-pasted.  Feel free to ignore all the
nits here and add a
// TODO(devlin): This file can be improved, and was copied from public docs.
Clean both up.

+// A generic onclick callback function.
+function genericOnClick(info, tab) {
+  console.log("item " + info.menuItemId + " was clicked");

[Devlin, 2016/12/15 17:14:41]

nit: prefer single quotes in js

+  console.log("info: " + JSON.stringify(info));
+  console.log("tab: " + JSON.stringify(tab));
+}
+
+// Create one test item for each context type.
+var contexts = ["page","selection","link","editable","image","video",
+                "audio"];
+for (var i = 0; i < contexts.length; i++) {

[Devlin, 2016/12/15 17:14:41]

for (let context of contexts)?

+  var context = contexts[i];
+  var title = "Test '" + context + "' menu item";
+  var id = chrome.contextMenus.create({"title": title, "contexts":[context],

[Devlin, 2016/12/15 17:14:41]

nit: no quotes around keys in objects.
nit: add a space after the ':' (next to contexts)

+                                       "onclick": genericOnClick});
+  console.log("'" + context + "' item:" + id);
+}
+
+
+// Create a parent item and two children.
+var parent = chrome.contextMenus.create({"title": "Test parent item"});
+var child1 = chrome.contextMenus.create(
+  {"title": "Child 1", "parentId": parent, "onclick": genericOnClick});
+var child2 = chrome.contextMenus.create(
+  {"title": "Child 2", "parentId": parent, "onclick": genericOnClick});
+console.log("parent:" + parent + " child1:" + child1 + " child2:" + child2);
+
+
+// Create some radio items.
+function radioOnClick(info, tab) {
+  console.log("radio item " + info.menuItemId +
+              " was clicked (previous checked state was "  +
+              info.wasChecked + ")");
+}
+var radio1 = chrome.contextMenus.create({"title": "Radio 1", "type": "radio",
+                                         "onclick":radioOnClick});
+var radio2 = chrome.contextMenus.create({"title": "Radio 2", "type": "radio",
+                                         "onclick":radioOnClick});
+console.log("radio1:" + radio1 + " radio2:" + radio2);
+
+
+// Create some checkbox items.
+function checkboxOnClick(info, tab) {
+  console.log(JSON.stringify(info));
+  console.log("checkbox item " + info.menuItemId +
+              " was clicked, state is now: " + info.checked +
+              "(previous state was " + info.wasChecked + ")");
+
+}
+var checkbox1 = chrome.contextMenus.create(
+  {"title": "Checkbox1", "type": "checkbox", "onclick":checkboxOnClick});
+var checkbox2 = chrome.contextMenus.create(
+  {"title": "Checkbox2", "type": "checkbox", "onclick":checkboxOnClick});
+console.log("checkbox1:" + checkbox1 + " checkbox2:" + checkbox2);
+
+
+// Intentionally create an invalid item, to show off error checking in the
+// create callback.
+console.log("About to try creating an invalid item - an error about " +
+            "item 999 should show up");
+chrome.contextMenus.create({"title": "Oops", "parentId":999}, function() {
+  if (chrome.extension.lastError) {
+    console.log("Got expected error: " + chrome.extension.lastError.message);
+  }
+});