`extension.isAllowed???Access` samples

chrome/common/extensions/docs/examples/extensions/proxy_configuration/proxy_form_controller.js

 // Copyright (c) 2011 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.
 
 /**
  * @fileoverview This file implements the ProxyFormController class, which
  * wraps a form element with logic that enables implementation of proxy
  * settings.
  *
  * @author mkwst@google.com (Mike West)
@@ skipping 107 matching lines @@
 ///////////////////////////////////////////////////////////////////////////////
 
 ProxyFormController.prototype = {
   /**
    * The form's current state.
    * @type {regular: ?ProxyConfig, incognito: ?ProxyConfig}
    * @private
    */
   config_: {regular: null, incognito: null},
 
+  /**
+   * Do we have access to incognito mode?
+   * @type {boolean}
+   * @private
+   */
+  isAllowedIncognitoAccess_: false,
 
   /**
    * @return {string} The PAC file URL (or an empty string).
    */
   get pacURL() {
     return document.getElementById('autoconfigURL').value;
   },
 
 
   /**
@@ skipping 178 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
   /**
    * Calls the proxy API to read the current settings, and populates the form
    * accordingly.
    *
    * @private
    */
   readCurrentState_: function() {
-    chrome.experimental.proxy.settings.get({incognito: false},
-        this.handleRegularState_.bind(this));
-    chrome.experimental.proxy.settings.get({incognito: true},
-        this.handleIncognitoState_.bind(this));
+    chrome.extension.isAllowedIncognitoAccess(
+        this.handleIncognitoAccessResponse_.bind(this));
   },
 
   /**
+   * Handles the respnse from `chrome.extension.isAllowedIncognitoAccess`
+   * We can't render the form until we know what our access level is, so
+   * we wait until we have confirmed incognito access levels before
+   * asking for the proxy state.
+   *
+   * @param {boolean} state The state of incognito access.
+   * @private
+   */
+  handleIncognitoAccessResponse_: function(state) {
+    this.isAllowedIncognitoAccess_ = state;
+    chrome.experimental.proxy.settings.get({incognito: false},
+        this.handleRegularState_.bind(this));
+    if (this.isAllowedIncognitoAccess_) {
+      chrome.experimental.proxy.settings.get({incognito: true},
+          this.handleIncognitoState_.bind(this));
+    }
+  },
+
+  /**
    * Handles the response from 'proxy.settings.get' for regular settings.
    *
    * @param {ProxyFormController.WrappedProxyConfig} c The proxy data and
    *     extension's level of control thereof.
    * @private
    */
   handleRegularState_: function(c) {
     if (c.levelOfControl === ProxyFormController.LevelOfControl.AVAILABLE ||
         c.levelOfControl === ProxyFormController.LevelOfControl.CONTROLLING) {
       this.recalcFormValues_(c.value);
@@ skipping 308 matching lines @@
   },
 
 
   /**
    * Sets the form's values based on a ProxyConfig.
    *
    * @param {!ProxyConfig} c The ProxyConfig object.
    * @private
    */
   recalcFormValues_: function(c) {
+    var button = document.getElementsByTagName('button')[0];
+    button.style.display = this.isAllowedIncognitoAccess_ ? 'block' : 'none';

[kurrik.chromium, 2011/03/21 22:13:02]

This button now wraps to another line.  I think I preferred it inline.

[Mike West, 2011/03/22 08:44:56]

Done.

+

[kurrik.chromium, 2011/03/21 22:13:02]

I think you could also add some UI indicating how to enable the extension's
incognito functionality.  Seems to be in the spirit of this function.

[Mike West, 2011/03/22 08:44:56]

Fair enough.  I've reworked this section entirely; I think you're right, it's
better with a message.

     // Normalize `auto_detect`
     if (c.mode === 'auto_detect')
       c.mode = 'pac_script';
     // Activate one of the groups, based on `mode`.
     this.changeActive_(document.getElementById(c.mode));
     // Populate the PAC script
     if (c.pacScript) {
       if (c.pacScript.url)
         this.pacURL = c.pacScript.url;
     } else {
@@ skipping 64 matching lines @@
     if (response.result !== null) {
       var error = response.result;
       console.error(error);  // TODO(mkwst): Do something more interesting
       this.generateAlert_(
           chrome.i18n.getMessage('errorProxyError', error.error),
           false);
     }
     chrome.extension.sendRequest({type: 'clearError'});
   }
 };