One accessibility tree per frame.

content/browser/accessibility/browser_accessibility_manager_win.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_WIN_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_WIN_H_
 
 #include <oleacc.h>
 
 #include "base/macros.h"
@@ skipping 25 matching lines @@
   // The IAccessible for the parent window.
   IAccessible* GetParentIAccessible();
 
   // Calls NotifyWinEvent if the parent window's IAccessible pointer is known.
   void MaybeCallNotifyWinEvent(DWORD event, BrowserAccessibility* node);
 
   // IAccessible2UsageObserver
   void OnIAccessible2Used() override;
 
   // BrowserAccessibilityManager methods
-  void OnWindowFocused() override;
   void UserIsReloading() override;
   void NotifyAccessibilityEvent(
       ui::AXEvent event_type, BrowserAccessibility* node) override;
+  bool CanFireEvents() override;
+  void FireFocusEvent(BrowserAccessibility* node) override;
 
   // Track this object and post a VISIBLE_DATA_CHANGED notification when
   // its container scrolls.
   // TODO(dmazzoni): remove once http://crbug.com/113483 is fixed.
   void TrackScrollingObject(BrowserAccessibilityWin* node);
 
   // Called when |accessible_hwnd_| is deleted by its parent.
   void OnAccessibleHwndDeleted();
 
  protected:
   // AXTree methods.
   void OnNodeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override;
   void OnNodeCreated(ui::AXTree* tree, ui::AXNode* node) override;
   void OnAtomicUpdateFinished(
       ui::AXTree* tree,
       bool root_changed,
       const std::vector<ui::AXTreeDelegate::Change>& changes) override;
 
  private:
   // Give BrowserAccessibilityManager::Create access to our constructor.
   friend class BrowserAccessibilityManager;
 
   // Track the most recent object that has been asked to scroll and
   // post a notification directly on it when it reaches its destination.
   // TODO(dmazzoni): remove once http://crbug.com/113483 is fixed.
   BrowserAccessibilityWin* tracked_scroll_object_;
 
-  // Set to true if we need to fire a focus event on the root as soon as
-  // possible.
-  bool focus_event_on_root_needed_;
-
-  // A flag to keep track of if we're inside the OnWindowFocused call stack
-  // so we don't keep calling it recursively.
-  bool inside_on_window_focused_;
-
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManagerWin);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_WIN_H_