Use unique IDs for accessibility nodes on Android

content/browser/accessibility/browser_accessibility_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_win.h"
 
 #include <UIAutomationClient.h>
 #include <UIAutomationCoreApi.h>
 
 #include <algorithm>
@@ skipping 24 matching lines @@
                               0x11cf,
                               {0xb6, 0x61, 0x00, 0xaa, 0x00, 0x4c, 0xd6, 0xd8}};
 const GUID GUID_IAccessibleContentDocument = {
     0xa5d8e1f3,
     0x3571,
     0x4d8f,
     {0x95, 0x21, 0x07, 0xed, 0x28, 0xfb, 0x07, 0x2e}};
 
 const base::char16 BrowserAccessibilityWin::kEmbeddedCharacter = L'\xfffc';
 
-// static
-LONG BrowserAccessibilityWin::next_unique_id_win_ =
-    base::win::kFirstBrowserAccessibilityManagerAccessibilityId;
-
 //
 // BrowserAccessibilityRelation
 //
 // A simple implementation of IAccessibleRelation, used to represent
 // a relationship between two accessible nodes in the tree.
 //
 
 class BrowserAccessibilityRelation
     : public CComObjectRootEx<CComMultiThreadModel>,
       public IAccessibleRelation {
@@ skipping 84 matching lines @@
     return E_INVALIDARG;
   }
 
   BrowserAccessibilityManager* manager = owner_->manager();
   BrowserAccessibility* result =
       manager->GetFromID(target_ids_[target_index]);
   if (!result || !result->instance_active())
     return E_FAIL;
 
   *target = static_cast<IAccessible*>(
-      result->ToBrowserAccessibilityWin()->NewReference());
+      ToBrowserAccessibilityWin(result)->NewReference());
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityRelation::get_targets(long max_targets,
                                                        IUnknown** targets,
                                                        long* n_targets) {
   if (!targets || !n_targets)
     return E_INVALIDARG;
 
   if (!owner_->instance_active())
@@ skipping 36 matching lines @@
 
 // static
 BrowserAccessibility* BrowserAccessibility::Create() {
   ui::win::CreateATLModuleIfNeeded();
   CComObject<BrowserAccessibilityWin>* instance;
   HRESULT hr = CComObject<BrowserAccessibilityWin>::CreateInstance(&instance);
   DCHECK(SUCCEEDED(hr));
   return instance->NewReference();
 }
 
-const BrowserAccessibilityWin* BrowserAccessibility::ToBrowserAccessibilityWin()
-    const {
-  return static_cast<const BrowserAccessibilityWin*>(this);
-}
-
-BrowserAccessibilityWin* BrowserAccessibility::ToBrowserAccessibilityWin() {
-  return static_cast<BrowserAccessibilityWin*>(this);
-}
-
 BrowserAccessibilityWin::BrowserAccessibilityWin()
     : win_attributes_(new WinAttributes()),
       previous_scroll_x_(0),
       previous_scroll_y_(0) {
-  // Start unique IDs at -1 and decrement each time, because get_accChild
-  // uses positive IDs to enumerate children, so we use negative IDs to
-  // clearly distinguish between indices and unique IDs.
-  unique_id_win_ = next_unique_id_win_;
-  if (next_unique_id_win_ ==
-          base::win::kLastBrowserAccessibilityManagerAccessibilityId) {
-    next_unique_id_win_ =
-        base::win::kFirstBrowserAccessibilityManagerAccessibilityId;
-  }
-  next_unique_id_win_--;
 }
 
 BrowserAccessibilityWin::~BrowserAccessibilityWin() {
   for (size_t i = 0; i < relations_.size(); ++i)
     relations_[i]->Release();
 }
 
 //
 // IAccessible methods.
 //
@@ skipping 31 matching lines @@
     return S_FALSE;
   }
 
   BrowserAccessibility* result = BrowserAccessibilityForPoint(point);
   if (result == this) {
     // Point is within this object.
     child->vt = VT_I4;
     child->lVal = CHILDID_SELF;
   } else {
     child->vt = VT_DISPATCH;
-    child->pdispVal = result->ToBrowserAccessibilityWin()->NewReference();
+    child->pdispVal = ToBrowserAccessibilityWin(result)->NewReference();
   }
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::accLocation(LONG* x_left,
                                                   LONG* y_top,
                                                   LONG* width,
                                                   LONG* height,
                                                   VARIANT var_id) {
   if (!instance_active())
@@ skipping 53 matching lines @@
       result = target->GetPreviousSibling();
       break;
   }
 
   if (!result) {
     end->vt = VT_EMPTY;
     return S_FALSE;
   }
 
   end->vt = VT_DISPATCH;
-  end->pdispVal = result->ToBrowserAccessibilityWin()->NewReference();
+  end->pdispVal = ToBrowserAccessibilityWin(result)->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_accChild(VARIANT var_child,
                                                    IDispatch** disp_child) {
   if (!instance_active())
     return E_FAIL;
 
   if (!disp_child)
     return E_INVALIDARG;
@@ skipping 135 matching lines @@
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_accParent(IDispatch** disp_parent) {
   if (!instance_active())
     return E_FAIL;
 
   if (!disp_parent)
     return E_INVALIDARG;
 
-  IAccessible* parent_obj = GetParent()->ToBrowserAccessibilityWin();
+  IAccessible* parent_obj = ToBrowserAccessibilityWin(GetParent());
   if (parent_obj == NULL) {
     // This happens if we're the root of the tree;
     // return the IAccessible for the window.
     parent_obj =
         manager()->ToBrowserAccessibilityManagerWin()->GetParentIAccessible();
     // |parent| can only be NULL if the manager was created before the parent
     // IAccessible was known and it wasn't subsequently set before a client
     // requested it. This has been fixed. |parent| may also be NULL during
     // destruction. Possible cases where this could occur include tabs being
     // dragged to a new window, etc.
@@ skipping 114 matching lines @@
   if (selected_count == 0) {
     selected->vt = VT_EMPTY;
     return S_OK;
   }
 
   if (selected_count == 1) {
     for (size_t i = 0; i < InternalChildCount(); ++i) {
       if (InternalGetChild(i)->HasState(ui::AX_STATE_SELECTED)) {
         selected->vt = VT_DISPATCH;
         selected->pdispVal =
-            InternalGetChild(i)->ToBrowserAccessibilityWin()->NewReference();
+            ToBrowserAccessibilityWin(InternalGetChild(i))->NewReference();
         return S_OK;
       }
     }
   }
 
   // Multiple items are selected.
   base::win::EnumVariant* enum_variant =
       new base::win::EnumVariant(selected_count);
   enum_variant->AddRef();
   unsigned long index = 0;
   for (size_t i = 0; i < InternalChildCount(); ++i) {
     if (InternalGetChild(i)->HasState(ui::AX_STATE_SELECTED)) {
       enum_variant->ItemAt(index)->vt = VT_DISPATCH;
       enum_variant->ItemAt(index)->pdispVal =
-        InternalGetChild(i)->ToBrowserAccessibilityWin()->NewReference();
+          ToBrowserAccessibilityWin(InternalGetChild(i))->NewReference();
       ++index;
     }
   }
   selected->vt = VT_UNKNOWN;
   selected->punkVal = static_cast<IUnknown*>(
       static_cast<base::win::IUnknownImpl*>(enum_variant));
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::accSelect(
@@ skipping 69 matching lines @@
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_uniqueID(LONG* unique_id) {
   if (!instance_active())
     return E_FAIL;
 
   if (!unique_id)
     return E_INVALIDARG;
 
-  *unique_id = unique_id_win_;
+  *unique_id = -unique_id_;
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_windowHandle(HWND* window_handle) {
   if (!instance_active())
     return E_FAIL;
 
   if (!window_handle)
     return E_INVALIDARG;
 
@@ skipping 517 matching lines @@
   const std::vector<int32_t>& unique_cell_ids =
       GetIntListAttribute(ui::AX_ATTR_UNIQUE_CELL_IDS);
   int cell_id_count = static_cast<int>(unique_cell_ids.size());
   if (cell_index < 0)
     return E_INVALIDARG;
   if (cell_index >= cell_id_count)
     return S_FALSE;
 
   int cell_id = unique_cell_ids[cell_index];
   BrowserAccessibilityWin* cell =
-      manager()->GetFromID(cell_id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(cell_id));
   int col_index;
   if (cell &&
       cell->GetIntAttribute(
           ui::AX_ATTR_TABLE_CELL_COLUMN_INDEX, &col_index)) {
     *column_index = col_index;
     return S_OK;
   }
 
   return S_FALSE;
 }
@@ skipping 84 matching lines @@
   }
 
   if (row < 0 || row >= rows)
     return E_INVALIDARG;
 
   const std::vector<int32_t>& cell_ids =
       GetIntListAttribute(ui::AX_ATTR_CELL_IDS);
   for (int i = 0; i < columns; ++i) {
     int cell_id = cell_ids[row * columns + i];
     BrowserAccessibilityWin* cell =
-        manager()->GetFromID(cell_id)->ToBrowserAccessibilityWin();
+        ToBrowserAccessibilityWin(manager()->GetFromID(cell_id));
     if (cell && cell->GetRole() == ui::AX_ROLE_ROW_HEADER) {
       base::string16 cell_name = cell->GetString16Attribute(
           ui::AX_ATTR_NAME);
       if (cell_name.size() > 0) {
         *description = SysAllocString(cell_name.c_str());
         return S_OK;
       }
 
       if (cell->description().size() > 0) {
         *description = SysAllocString(cell->description().c_str());
@@ skipping 24 matching lines @@
     return S_FALSE;
   }
 
   if (row < 0 || row >= rows || column < 0 || column >= columns)
     return E_INVALIDARG;
 
   const std::vector<int32_t>& cell_ids =
       GetIntListAttribute(ui::AX_ATTR_CELL_IDS);
   int cell_id = cell_ids[row * columns + column];
   BrowserAccessibilityWin* cell =
-      manager()->GetFromID(cell_id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(cell_id));
   int rowspan;
   if (cell &&
       cell->GetIntAttribute(
           ui::AX_ATTR_TABLE_CELL_ROW_SPAN, &rowspan) &&
       rowspan >= 1) {
     *n_rows_spanned = rowspan;
     return S_OK;
   }
 
   return S_FALSE;
@@ skipping 17 matching lines @@
   const std::vector<int32_t>& unique_cell_ids =
       GetIntListAttribute(ui::AX_ATTR_UNIQUE_CELL_IDS);
   int cell_id_count = static_cast<int>(unique_cell_ids.size());
   if (cell_index < 0)
     return E_INVALIDARG;
   if (cell_index >= cell_id_count)
     return S_FALSE;
 
   int cell_id = unique_cell_ids[cell_index];
   BrowserAccessibilityWin* cell =
-      manager()->GetFromID(cell_id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(cell_id));
   int cell_row_index;
   if (cell &&
       cell->GetIntAttribute(
           ui::AX_ATTR_TABLE_CELL_ROW_INDEX, &cell_row_index)) {
     *row_index = cell_row_index;
     return S_OK;
   }
 
   return S_FALSE;
 }
@@ skipping 108 matching lines @@
   const std::vector<int32_t>& unique_cell_ids =
       GetIntListAttribute(ui::AX_ATTR_UNIQUE_CELL_IDS);
   int cell_id_count = static_cast<int>(unique_cell_ids.size());
   if (index < 0)
     return E_INVALIDARG;
   if (index >= cell_id_count)
     return S_FALSE;
 
   int cell_id = unique_cell_ids[index];
   BrowserAccessibilityWin* cell =
-      manager()->GetFromID(cell_id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(cell_id));
   int rowspan;
   int colspan;
   if (cell &&
       cell->GetIntAttribute(
           ui::AX_ATTR_TABLE_CELL_ROW_SPAN, &rowspan) &&
       cell->GetIntAttribute(
           ui::AX_ATTR_TABLE_CELL_COLUMN_SPAN, &colspan) &&
       rowspan >= 1 &&
       colspan >= 1) {
     *row_extents = rowspan;
@@ skipping 138 matching lines @@
   }
   if (columns <= 0 || rows <= 0 || column < 0 || column >= columns)
     return S_FALSE;
 
   const std::vector<int32_t>& cell_ids =
       table->GetIntListAttribute(ui::AX_ATTR_CELL_IDS);
 
   for (int i = 0; i < rows; ++i) {
     int cell_id = cell_ids[i * columns + column];
     BrowserAccessibilityWin* cell =
-        manager()->GetFromID(cell_id)->ToBrowserAccessibilityWin();
+        ToBrowserAccessibilityWin(manager()->GetFromID(cell_id));
     if (cell && cell->GetRole() == ui::AX_ROLE_COLUMN_HEADER)
       (*n_column_header_cells)++;
   }
 
   *cell_accessibles = static_cast<IUnknown**>(CoTaskMemAlloc(
       (*n_column_header_cells) * sizeof(cell_accessibles[0])));
   int index = 0;
   for (int i = 0; i < rows; ++i) {
     int cell_id = cell_ids[i * columns + column];
     BrowserAccessibility* cell = manager()->GetFromID(cell_id);
     if (cell && cell->GetRole() == ui::AX_ROLE_COLUMN_HEADER) {
       (*cell_accessibles)[index] = static_cast<IAccessible*>(
-          cell->ToBrowserAccessibilityWin()->NewReference());
+          ToBrowserAccessibilityWin(cell)->NewReference());
       ++index;
     }
   }
 
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_columnIndex(long* column_index) {
   if (!instance_active())
     return E_FAIL;
@@ skipping 76 matching lines @@
   }
 
   *cell_accessibles = static_cast<IUnknown**>(CoTaskMemAlloc(
       (*n_row_header_cells) * sizeof(cell_accessibles[0])));
   int index = 0;
   for (int i = 0; i < columns; ++i) {
     int cell_id = cell_ids[row * columns + i];
     BrowserAccessibility* cell = manager()->GetFromID(cell_id);
     if (cell && cell->GetRole() == ui::AX_ROLE_ROW_HEADER) {
       (*cell_accessibles)[index] = static_cast<IAccessible*>(
-          cell->ToBrowserAccessibilityWin()->NewReference());
+          ToBrowserAccessibilityWin(cell)->NewReference());
       ++index;
     }
   }
 
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_rowIndex(long* row_index) {
   if (!instance_active())
     return E_FAIL;
@@ skipping 74 matching lines @@
 
   BrowserAccessibility* find_table = GetParent();
   while (find_table && find_table->GetRole() != ui::AX_ROLE_TABLE)
     find_table = find_table->GetParent();
   if (!find_table) {
     NOTREACHED();
     return S_FALSE;
   }
 
   *table = static_cast<IAccessibleTable*>(
-      find_table->ToBrowserAccessibilityWin()->NewReference());
+      ToBrowserAccessibilityWin(find_table)->NewReference());
 
   return S_OK;
 }
 
 //
 // IAccessibleText methods.
 //
 
 STDMETHODIMP BrowserAccessibilityWin::get_nCharacters(LONG* n_characters) {
   if (!instance_active())
@@ skipping 421 matching lines @@
     return E_FAIL;
 
   if (!hyperlink ||
       index < 0 ||
       index >= static_cast<long>(hyperlinks().size())) {
     return E_INVALIDARG;
   }
 
   int32_t id = hyperlinks()[index];
   BrowserAccessibilityWin* child =
-      manager()->GetFromID(id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(id));
   if (child) {
     *hyperlink = static_cast<IAccessibleHyperlink*>(child->NewReference());
     return S_OK;
   }
 
   return E_FAIL;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_hyperlinkIndex(
     long char_index,
@@ skipping 77 matching lines @@
   if (!instance_active() || !IsHyperlink())
     return E_FAIL;
 
   if (!index)
     return E_INVALIDARG;
 
   int32_t hypertext_offset = 0;
   const auto parent = GetParent();
   if (parent) {
     hypertext_offset =
-        parent->ToBrowserAccessibilityWin()->GetHypertextOffsetFromChild(*this);
+        ToBrowserAccessibilityWin(parent)->GetHypertextOffsetFromChild(*this);
   }
   *index = static_cast<LONG>(hypertext_offset);
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_endIndex(long* index) {
   LONG start_index;
   HRESULT hr = get_startIndex(&start_index);
   if (hr == S_OK)
     *index = start_index + 1;
@@ skipping 220 matching lines @@
 
   base::string16 tag;
   if (GetString16Attribute(ui::AX_ATTR_HTML_TAG, &tag))
     *node_name = SysAllocString(tag.c_str());
   else
     *node_name = NULL;
 
   *name_space_id = 0;
   *node_value = SysAllocString(value().c_str());
   *num_children = PlatformChildCount();
-  *unique_id = unique_id_win_;
+  *unique_id = -unique_id_;
 
   if (GetRole() == ui::AX_ROLE_ROOT_WEB_AREA ||
     GetRole() == ui::AX_ROLE_WEB_AREA) {
     *node_type = NODETYPE_DOCUMENT;
   } else if (IsTextOnlyObject()) {
     *node_type = NODETYPE_TEXT;
   } else {
     *node_type = NODETYPE_ELEMENT;
   }
 
@@ skipping 117 matching lines @@
       IA2_SCROLL_TYPE_TOP_LEFT : IA2_SCROLL_TYPE_ANYWHERE);
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_parentNode(ISimpleDOMNode** node) {
   if (!instance_active())
     return E_FAIL;
 
   if (!node)
     return E_INVALIDARG;
 
-  *node = GetParent()->ToBrowserAccessibilityWin()->NewReference();
+  *node = ToBrowserAccessibilityWin(GetParent())->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_firstChild(ISimpleDOMNode** node)  {
   if (!instance_active())
     return E_FAIL;
 
   if (!node)
     return E_INVALIDARG;
 
   if (PlatformChildCount() == 0) {
     *node = NULL;
     return S_FALSE;
   }
 
-  *node = PlatformGetChild(0)->ToBrowserAccessibilityWin()->NewReference();
+  *node = ToBrowserAccessibilityWin(PlatformGetChild(0))->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_lastChild(ISimpleDOMNode** node) {
   if (!instance_active())
     return E_FAIL;
 
   if (!node)
     return E_INVALIDARG;
 
   if (PlatformChildCount() == 0) {
     *node = NULL;
     return S_FALSE;
   }
 
-  *node = PlatformGetChild(PlatformChildCount() - 1)
-      ->ToBrowserAccessibilityWin()->NewReference();
+  *node = ToBrowserAccessibilityWin(
+      PlatformGetChild(PlatformChildCount() - 1))->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_previousSibling(
     ISimpleDOMNode** node) {
   if (!instance_active())
     return E_FAIL;
 
   if (!node)
     return E_INVALIDARG;
 
   if (!GetParent() || GetIndexInParent() <= 0) {
     *node = NULL;
     return S_FALSE;
   }
 
-  *node = GetParent()->InternalGetChild(GetIndexInParent() - 1)->
-      ToBrowserAccessibilityWin()->NewReference();
+  *node = ToBrowserAccessibilityWin(
+      GetParent()->InternalGetChild(GetIndexInParent() - 1))->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_nextSibling(ISimpleDOMNode** node) {
   if (!instance_active())
     return E_FAIL;
 
   if (!node)
     return E_INVALIDARG;
 
   if (!GetParent() ||
       GetIndexInParent() < 0 ||
       GetIndexInParent() >= static_cast<int>(
           GetParent()->InternalChildCount()) - 1) {
     *node = NULL;
     return S_FALSE;
   }
 
-  *node = GetParent()->InternalGetChild(GetIndexInParent() + 1)->
-      ToBrowserAccessibilityWin()->NewReference();
+  *node = ToBrowserAccessibilityWin(
+      GetParent()->InternalGetChild(GetIndexInParent() + 1))->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_childAt(
     unsigned int child_index,
     ISimpleDOMNode** node) {
   if (!instance_active())
     return E_FAIL;
 
   if (!node)
     return E_INVALIDARG;
 
   if (child_index >= PlatformChildCount())
     return E_INVALIDARG;
 
   BrowserAccessibility* child = PlatformGetChild(child_index);
   if (!child) {
     *node = NULL;
     return S_FALSE;
   }
 
-  *node = child->ToBrowserAccessibilityWin()->NewReference();
+  *node = ToBrowserAccessibilityWin(child)->NewReference();
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_innerHTML(BSTR* innerHTML) {
   return E_NOTIMPL;
 }
 
 STDMETHODIMP
 BrowserAccessibilityWin::get_localInterface(void** local_interface) {
   return E_NOTIMPL;
@@ skipping 98 matching lines @@
   if (riid == IID_IAccessible2)
     BrowserAccessibilityStateImpl::GetInstance()->EnableAccessibility();
 
   if (guid_service == GUID_IAccessibleContentDocument) {
     // Special Mozilla extension: return the accessible for the root document.
     // Screen readers use this to distinguish between a document loaded event
     // on the root document vs on an iframe.
     BrowserAccessibility* node = this;
     while (node->GetParent())
       node = node->GetParent()->manager()->GetRoot();
-    return node->ToBrowserAccessibilityWin()->QueryInterface(
+    return ToBrowserAccessibilityWin(node)->QueryInterface(
         IID_IAccessible2, object);
   }
 
   if (guid_service == IID_IAccessible ||
       guid_service == IID_IAccessible2 ||
       guid_service == IID_IAccessibleAction ||
       guid_service == IID_IAccessibleApplication ||
       guid_service == IID_IAccessibleHyperlink ||
       guid_service == IID_IAccessibleHypertext ||
       guid_service == IID_IAccessibleImage ||
@@ skipping 336 matching lines @@
     return;
   }
 
   // Construct the hypertext for this node, which contains the concatenation
   // of all of the static text and widespace of this node's children and an
   // embedded object character for all the other children. Build up a map from
   // the character index of each embedded object character to the id of the
   // child object it points to.
   for (unsigned int i = 0; i < PlatformChildCount(); ++i) {
     BrowserAccessibilityWin* child =
-        PlatformGetChild(i)->ToBrowserAccessibilityWin();
+        ToBrowserAccessibilityWin(PlatformGetChild(i));
     DCHECK(child);
     // Similar to Firefox, we don't expose text-only objects in IA2 hypertext.
     if (child->IsTextOnlyObject()) {
       win_attributes_->hypertext += child->name();
     } else {
       int32_t char_offset = static_cast<int32_t>(GetText().size());
       int32_t child_id = child->GetId();
       int32_t index = hyperlinks().size();
       win_attributes_->hyperlink_offset_to_index[char_offset] = index;
       win_attributes_->hyperlinks.push_back(child_id);
@@ skipping 83 matching lines @@
       manager->MaybeCallNotifyWinEvent(IA2_EVENT_TEXT_REMOVED, this);
     }
     if (new_len > 0) {
       // In-process screen readers may call IAccessibleText::get_newText
       // in reaction to this event to retrieve the text that was inserted.
       manager->MaybeCallNotifyWinEvent(IA2_EVENT_TEXT_INSERTED, this);
     }
 
     // Changing a static text node can affect the IAccessibleText hypertext
     // of the parent node, so force an update on the parent.
-    BrowserAccessibilityWin* parent = GetParent()->ToBrowserAccessibilityWin();
+    BrowserAccessibilityWin* parent = ToBrowserAccessibilityWin(GetParent());
     if (parent && IsTextOnlyObject() &&
         name() != old_win_attributes_->name) {
       parent->UpdateStep1ComputeWinAttributes();
       parent->UpdateStep2ComputeHypertext();
       parent->UpdateStep3FireEvents(false);
     }
   }
 
   old_win_attributes_.reset(nullptr);
 }
@@ skipping 28 matching lines @@
 BrowserAccessibilityWin* BrowserAccessibilityWin::GetTargetFromChildID(
     const VARIANT& var_id) {
   if (var_id.vt != VT_I4)
     return NULL;
 
   LONG child_id = var_id.lVal;
   if (child_id == CHILDID_SELF)
     return this;
 
   if (child_id >= 1 && child_id <= static_cast<LONG>(PlatformChildCount()))
-    return PlatformGetChild(child_id - 1)->ToBrowserAccessibilityWin();
+    return ToBrowserAccessibilityWin(PlatformGetChild(child_id - 1));
 
-  return manager()->ToBrowserAccessibilityManagerWin()->
-      GetFromUniqueIdWin(child_id);
+  return ToBrowserAccessibilityWin(
+      BrowserAccessibility::GetFromUniqueID(-child_id));
 }
 
 HRESULT BrowserAccessibilityWin::GetStringAttributeAsBstr(
     ui::AXStringAttribute attribute,
     BSTR* value_bstr) {
   base::string16 str;
 
   if (!GetString16Attribute(attribute, &str))
     return S_FALSE;
 
@@ skipping 52 matching lines @@
         base::ASCIIToUTF16(ia2_attr) + L":" +
         base::IntToString16(value));
   }
 }
 
 bool BrowserAccessibilityWin::IsHyperlink() const {
   int32_t hyperlink_index = -1;
   const auto parent = GetParent();
   if (parent) {
     hyperlink_index =
-        parent->ToBrowserAccessibilityWin()->GetHyperlinkIndexFromChild(*this);
+        ToBrowserAccessibilityWin(parent)->GetHyperlinkIndexFromChild(*this);
   }
 
   if (hyperlink_index >= 0)
     return true;
   return false;
 }
 
 int32_t BrowserAccessibilityWin::GetHyperlinkIndexFromChild(
     const BrowserAccessibilityWin& child) const {
   if (hyperlinks().empty())
@@ skipping 26 matching lines @@
   // and so |InternalChild...| functions need to be used. Also, direct text-only
   // children should not be present at tree roots and so no cross-tree traversal
   // is necessary.)
   if (child.IsTextOnlyObject()) {
     int32_t hypertextOffset = 0;
     int32_t index_in_parent = child.GetIndexInParent();
     DCHECK_GE(index_in_parent, 0);
     DCHECK_LT(index_in_parent, static_cast<int32_t>(InternalChildCount()));
     for (uint32_t i = 0; i < static_cast<uint32_t>(index_in_parent); ++i) {
       const BrowserAccessibilityWin* sibling =
-          InternalGetChild(i)->ToBrowserAccessibilityWin();
+          ToBrowserAccessibilityWin(InternalGetChild(i));
       DCHECK(sibling);
       if (sibling->IsTextOnlyObject())
         hypertextOffset += sibling->GetText().size();
       else
         ++hypertextOffset;
     }
     return hypertextOffset;
   }
 
   int32_t hyperlink_index = GetHyperlinkIndexFromChild(child);
   if (hyperlink_index < 0)
     return -1;
 
   return GetHypertextOffsetFromHyperlinkIndex(hyperlink_index);
 }
 
 int32_t BrowserAccessibilityWin::GetHypertextOffsetFromDescendant(
     const BrowserAccessibilityWin& descendant) const {
-  auto parent_object = descendant.GetParent()->ToBrowserAccessibilityWin();
+  auto parent_object = ToBrowserAccessibilityWin(descendant.GetParent());
   auto current_object = const_cast<BrowserAccessibilityWin*>(&descendant);
   while (parent_object && parent_object != this) {
     current_object = parent_object;
-    parent_object = current_object->GetParent()->ToBrowserAccessibilityWin();
+    parent_object = ToBrowserAccessibilityWin(current_object->GetParent());
   }
   if (!parent_object)
     return -1;
 
   return parent_object->GetHypertextOffsetFromChild(*current_object);
 }
 
 int BrowserAccessibilityWin::GetHypertextOffsetFromEndpoint(
     const BrowserAccessibilityWin& endpoint_object,
     int endpoint_offset) const {
@@ skipping 61 matching lines @@
   if (endpoint_index_in_common_parent > index_in_common_parent)
     return GetText().size();
 
   NOTREACHED();
   return -1;
 }
 
 int BrowserAccessibilityWin::GetSelectionAnchor() const {
   int32_t anchor_id = manager()->GetTreeData().sel_anchor_object_id;
   const auto anchor_object =
-      manager()->GetFromID(anchor_id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(anchor_id));
   if (!anchor_object)
     return -1;
 
   int anchor_offset = manager()->GetTreeData().sel_anchor_offset;
   return GetHypertextOffsetFromEndpoint(*anchor_object, anchor_offset);
 }
 
 int BrowserAccessibilityWin::GetSelectionFocus() const {
   int32_t focus_id = manager()->GetTreeData().sel_focus_object_id;
   const auto focus_object =
-      manager()->GetFromID(focus_id)->ToBrowserAccessibilityWin();
+      ToBrowserAccessibilityWin(manager()->GetFromID(focus_id));
   if (!focus_object)
     return -1;
 
   int focus_offset = manager()->GetTreeData().sel_focus_offset;
   return GetHypertextOffsetFromEndpoint(*focus_object, focus_offset);
 }
 
 void BrowserAccessibilityWin::GetSelectionOffsets(
     int* selection_start, int* selection_end) const {
   DCHECK(selection_start && selection_end);
@@ skipping 177 matching lines @@
     return GetWordStartBoundary(static_cast<int>(start_offset), direction);
 
   ui::TextBoundaryType boundary = IA2TextBoundaryToTextBoundary(ia2_boundary);
   const std::vector<int32_t>& line_breaks =
       GetIntListAttribute(ui::AX_ATTR_LINE_BREAKS);
   return ui::FindAccessibleTextBoundary(
       text, line_breaks, boundary, start_offset, direction);
 }
 
 BrowserAccessibilityWin* BrowserAccessibilityWin::GetFromID(int32_t id) {
-  return manager()->GetFromID(id)->ToBrowserAccessibilityWin();
+  return ToBrowserAccessibilityWin(manager()->GetFromID(id));
 }
 
 bool BrowserAccessibilityWin::IsListBoxOptionOrMenuListOption() {
   if (!GetParent())
     return false;
 
   int32_t role = GetRole();
   int32_t parent_role = GetParent()->GetRole();
 
   if (role == ui::AX_ROLE_LIST_BOX_OPTION &&
@@ skipping 634 matching lines @@
   if (!ia2_role)
     ia2_role = ia_role;
 
   win_attributes_->ia_role = ia_role;
   win_attributes_->ia_state = ia_state;
   win_attributes_->role_name = role_name;
   win_attributes_->ia2_role = ia2_role;
   win_attributes_->ia2_state = ia2_state;
 }
 
+BrowserAccessibilityWin* ToBrowserAccessibilityWin(BrowserAccessibility* obj) {
+  DCHECK(!obj || obj->IsNative());
+  return static_cast<BrowserAccessibilityWin*>(obj);
+}
+
+const BrowserAccessibilityWin*
+ToBrowserAccessibilityWin(const BrowserAccessibility* obj) {
+  DCHECK(!obj || obj->IsNative());
+  return static_cast<const BrowserAccessibilityWin*>(obj);
+}
+
 }  // namespace content