Reland of Uses the activedescendant_changed event received from Blink to fire the right focus event

content/browser/accessibility/browser_accessibility_manager_win.cc

 // 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.
 
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
@@ skipping 86 matching lines @@
 void BrowserAccessibilityManagerWin::UserIsReloading() {
   if (GetRoot()) {
     (new BrowserAccessibilityEventWin(
         BrowserAccessibilityEvent::FromRenderFrameHost,
         ui::AX_EVENT_NONE,
         IA2_EVENT_DOCUMENT_RELOAD,
         GetRoot()))->Fire();
   }
 }
 
+BrowserAccessibility* BrowserAccessibilityManagerWin::GetFocus() {
+  BrowserAccessibility* focus = BrowserAccessibilityManager::GetFocus();
+  return GetActiveDescendant(focus);
+}
+
 void BrowserAccessibilityManagerWin::NotifyAccessibilityEvent(
     BrowserAccessibilityEvent::Source source,
     ui::AXEvent event_type,
     BrowserAccessibility* node) {
   bool can_fire_events = CanFireEvents();
 
   // TODO(dmazzoni): A better fix would be to always have a HWND.
   // http://crbug.com/521877
   if (event_type == ui::AX_EVENT_LOAD_COMPLETE && can_fire_events)
     load_complete_pending_ = false;
@@ skipping 107 matching lines @@
   BrowserAccessibilityDelegate* root_delegate = GetDelegateFromRootManager();
   if (!root_delegate)
     return false;
   HWND hwnd = root_delegate->AccessibilityGetAcceleratedWidget();
   return hwnd != nullptr;
 }
 
 void BrowserAccessibilityManagerWin::FireFocusEvent(
     BrowserAccessibilityEvent::Source source,
     BrowserAccessibility* node) {
+  DCHECK(node);
   // On Windows, we always fire a FOCUS event on the root of a frame before
   // firing a focus event within that frame.
   if (node->manager() != last_focused_manager_ &&
       node != node->manager()->GetRoot()) {
     BrowserAccessibilityEvent::Create(source,
                                       ui::AX_EVENT_FOCUS,
                                       node->manager()->GetRoot())->Fire();
   }
 
   BrowserAccessibilityManager::FireFocusEvent(source, node);
@@ skipping 77 matching lines @@
 
 void BrowserAccessibilityManagerWin::TrackScrollingObject(
     BrowserAccessibilityWin* node) {
   if (tracked_scroll_object_)
     tracked_scroll_object_->Release();
   tracked_scroll_object_ = node;
   tracked_scroll_object_->AddRef();
 }
 
 }  // namespace content