PageActions can now specify multiple icons and switch between them...

chrome/renderer/resources/extension_process_bindings.js

 // Copyright (c) 2009 The chrome Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // -----------------------------------------------------------------------------
 // NOTE: If you change this file you need to touch renderer_resources.grd to
 // have your change take effect.
 // -----------------------------------------------------------------------------
 
 var chrome;
@@ skipping 340 matching lines @@
     validate(arguments, arguments.callee.params);
     sendRequest(EnablePageAction, [pageActionId, action]);
   }
 
   chrome.pageActions.enableForTab.params = [
     chrome.types.str,
     {
       type: "object",
       properties: {
         tabId: chrome.types.pInt,
-        url: chrome.types.str
+        url: chrome.types.str,
+        title: chrome.types.optStr,
+        iconId: chrome.types.optPInt,
       },
       optional: false
     }
   ];
 
   chrome.pageActions.disableForTab = function(pageActionId, action) {
     validate(arguments, arguments.callee.params);
     sendRequest(DisablePageAction, [pageActionId, action]);
   }
 
@@ skipping 162 matching lines @@
     window.addEventListener('unload', function() {
         UnregisterExtension(extensionId); }, false);
     delete chrome.self.register_;
   }
 
   chrome.self.getViews = function() {
     return GetViews();
   }
 })();