Fix accessibility with out-of-process iframes.

content/browser/accessibility/browser_accessibility.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.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 42 matching lines @@
     case ui::AX_ROLE_SLIDER:
     case ui::AX_ROLE_STATIC_TEXT:
     case ui::AX_ROLE_TEXT_FIELD:
       return true;
     default:
       return false;
   }
 }
 
 uint32 BrowserAccessibility::PlatformChildCount() const {
+  if (GetBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST)) {
+    // Check if the child frame currently exists.
+    if (manager_->delegate()->AccessibilityGetChildFrame(GetId()))
+      return 1;
+
+    return 0;
+  }
+
   return PlatformIsLeaf() ? 0 : InternalChildCount();
 }
 
 bool BrowserAccessibility::IsNative() const {
   return false;
 }
 
 bool BrowserAccessibility::IsDescendantOf(
     BrowserAccessibility* ancestor) {
   if (this == ancestor) {
     return true;
   } else if (GetParent()) {
     return GetParent()->IsDescendantOf(ancestor);
   }
 
   return false;
 }
 
 BrowserAccessibility* BrowserAccessibility::PlatformGetChild(
     uint32 child_index) const {
-  DCHECK(child_index < InternalChildCount());
-  BrowserAccessibility* result = InternalGetChild(child_index);
+  DCHECK(child_index < PlatformChildCount());
+  BrowserAccessibility* result = nullptr;
 
-  if (result->HasBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST)) {
+  if (GetBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST)) {
     BrowserAccessibilityManager* child_manager =
-        manager_->delegate()->AccessibilityGetChildFrame(result->GetId());
+        manager_->delegate()->AccessibilityGetChildFrame(GetId());
     if (child_manager)
       result = child_manager->GetRoot();
+  } else {
+    result = InternalGetChild(child_index);
   }
 
   return result;
 }
 
 bool BrowserAccessibility::PlatformIsChildOfLeaf() const {
   BrowserAccessibility* ancestor = GetParent();
   while (ancestor) {
     if (ancestor->PlatformIsLeaf())
       return true;
@@ skipping 42 matching lines @@
     return manager_->GetFromAXNode(parent);
 
   if (!manager_->delegate())
     return NULL;
 
   BrowserAccessibility* host_node =
       manager_->delegate()->AccessibilityGetParentFrame();
   if (!host_node)
     return NULL;
 
-  return host_node->GetParent();
+  return host_node;
 }
 
 int32 BrowserAccessibility::GetIndexInParent() const {
   return node_ ? node_->index_in_parent() : -1;
 }
 
 int32 BrowserAccessibility::GetId() const {
   return node_ ? node_->id() : -1;
 }
 
@@ skipping 592 matching lines @@
       }
       need_to_offset_web_area = true;
     }
     parent = parent->GetParentForBoundsCalculation();
   }
 
   return bounds;
 }
 
 }  // namespace content