Fix bad focus state tracking

chrome/renderer/resources/extensions/automation_custom_bindings.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.
 
 // Custom bindings for the automation API.
 var AutomationNode = require('automationNode').AutomationNode;
 var AutomationRootNode = require('automationNode').AutomationRootNode;
 var automation = require('binding').Binding.create('automation');
 var automationInternal =
     require('binding').Binding.create('automationInternal').generate();
 var eventBindings = require('event_bindings');
 var Event = eventBindings.Event;
 var exceptionHandler = require('uncaught_exception_handler');
 var forEach = require('utils').forEach;
 var lastError = require('lastError');
 var logging = requireNative('logging');
 var nativeAutomationInternal = requireNative('automationInternal');
 var GetRoutingID = nativeAutomationInternal.GetRoutingID;
 var GetSchemaAdditions = nativeAutomationInternal.GetSchemaAdditions;
 var DestroyAccessibilityTree =
     nativeAutomationInternal.DestroyAccessibilityTree;
 var GetIntAttribute = nativeAutomationInternal.GetIntAttribute;
 var StartCachingAccessibilityTrees =
     nativeAutomationInternal.StartCachingAccessibilityTrees;
 var AddTreeChangeObserver = nativeAutomationInternal.AddTreeChangeObserver;
 var RemoveTreeChangeObserver =
     nativeAutomationInternal.RemoveTreeChangeObserver;
-var GetFocus = nativeAutomationInternal.GetFocus;
+var GetFocusNative = nativeAutomationInternal.GetFocus;
 var schema = GetSchemaAdditions();
 
 /**
  * A namespace to export utility functions to other files in automation.
  */
 window.automationUtil = function() {};
 
 // TODO(aboxhall): Look into using WeakMap
 var idToCallback = {};
 
@@ skipping 28 matching lines @@
  */
 automationUtil.nextTreeChangeObserverId = 1;
 
 /**
  * @type {AutomationNode} The current focused node. This is only updated
  *   when calling automationUtil.updateFocusedNode.
  */
 automationUtil.focusedNode = null;
 
 /**
+ * Gets the currently focused AutomationNode.
+ * @return {AutomationNode}
+ */
+automationUtil.getFocus = function() {
+  var focusedNodeInfo = GetFocusNative(DESKTOP_TREE_ID);
+  if (!focusedNodeInfo)
+    return null;
+  var tree = AutomationRootNode.getOrCreate(focusedNodeInfo.treeId);
+  if (tree)
+    return privates(tree).impl.get(focusedNodeInfo.nodeId);
+};
+
+/**
  * Update automationUtil.focusedNode to be the node that currently has focus.
  */
 automationUtil.updateFocusedNode = function() {
-  automationUtil.focusedNode = null;
-  var focusedNodeInfo = GetFocus(DESKTOP_TREE_ID);
-  if (!focusedNodeInfo)
-    return;
-  var tree = AutomationRootNode.getOrCreate(focusedNodeInfo.treeId);
-  if (tree) {
-    automationUtil.focusedNode =
-        privates(tree).impl.get(focusedNodeInfo.nodeId);
-  }
+  automationUtil.focusedNode = automationUtil.getFocus();
 };
 
 automation.registerCustomHook(function(bindingsAPI) {
   var apiFunctions = bindingsAPI.apiFunctions;
 
   // TODO(aboxhall, dtseng): Make this return the speced AutomationRootNode obj.
   apiFunctions.setHandleRequest('getTree', function getTree(tabID, callback) {
     var routingID = GetRoutingID();
     StartCachingAccessibilityTrees();
 
@@ skipping 35 matching lines @@
           callback();
           return;
         }
       });
     } else {
       callback(desktopTree);
     }
   });
 
   apiFunctions.setHandleRequest('getFocus', function(callback) {
-    automationUtil.updateFocusedNode();
-    callback(automationUtil.focusedNode);
+    callback(automationUtil.getFocus());
   });
 
   function removeTreeChangeObserver(observer) {
     for (var id in automationUtil.treeChangeObserverMap) {
       if (automationUtil.treeChangeObserverMap[id] == observer) {
         RemoveTreeChangeObserver(id);
         delete automationUtil.treeChangeObserverMap[id];
         return;
       }
     }
@@ skipping 177 matching lines @@
 
 var binding = automation.generate();
 // Add additional accessibility bindings not specified in the automation IDL.
 // Accessibility and automation share some APIs (see
 // ui/accessibility/ax_enums.idl).
 forEach(schema, function(k, v) {
   binding[k] = v;
 });
 
 exports.$set('binding', binding);