Implement BrowserAccessibility accNavigate() in terms of AXPlatformNodeWin.

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 473 matching lines @@
     return E_FAIL;
 
   return GetPlatformNodeWin()->accLocation(x_left, y_top, width, height,
                                            var_id);
 }
 
 STDMETHODIMP BrowserAccessibilityWin::accNavigate(LONG nav_dir,
                                                   VARIANT start,
                                                   VARIANT* end) {
   WIN_ACCESSIBILITY_API_HISTOGRAM(UMA_API_ACC_NAVIGATE);
   BrowserAccessibilityWin* target = GetTargetFromChildID(start);

[dougt, 2017/04/08 06:49:30]

I mentioned this elsewhere, I think we should do this target matching from
within the platform node code.

   if (!target)
     return E_INVALIDARG;
 
-  if ((nav_dir == NAVDIR_LASTCHILD || nav_dir == NAVDIR_FIRSTCHILD) &&
-      start.lVal != CHILDID_SELF) {
-    // MSAA states that navigating to first/last child can only be from self.
-    return E_INVALIDARG;
+  // Forward all directions but NAVDIR_ to the platform node implementation.
+  if (nav_dir != NAVDIR_DOWN && nav_dir != NAVDIR_UP &&
+      nav_dir != NAVDIR_LEFT && nav_dir != NAVDIR_RIGHT) {
+    return target->GetPlatformNodeWin()->accNavigate(nav_dir, start, end);
   }
 
-  uint32_t child_count = target->PlatformChildCount();
   BrowserAccessibility* result = nullptr;
   switch (nav_dir) {
     case NAVDIR_DOWN:
       result = target->GetTableCell(GetTableRow() + GetTableRowSpan(),
                                     GetTableColumn());
       break;
     case NAVDIR_UP:
       result = target->GetTableCell(GetTableRow() - 1, GetTableColumn());
       break;
     case NAVDIR_LEFT:
       result = target->GetTableCell(GetTableRow(), GetTableColumn() - 1);
       break;
     case NAVDIR_RIGHT:
       result = target->GetTableCell(GetTableRow(),
                                     GetTableColumn() + GetTableColumnSpan());
       break;
-    case NAVDIR_FIRSTCHILD:
-      if (child_count > 0)
-        result = target->PlatformGetChild(0);
-      break;
-    case NAVDIR_LASTCHILD:
-      if (child_count > 0)
-        result = target->PlatformGetChild(child_count - 1);
-      break;
-    case NAVDIR_NEXT:
-      result = target->GetNextSibling();
-      break;
-    case NAVDIR_PREVIOUS:
-      result = target->GetPreviousSibling();
-      break;
   }
 
   if (!result) {
     end->vt = VT_EMPTY;
     return S_FALSE;
   }
 
   end->vt = VT_DISPATCH;
   end->pdispVal = ToBrowserAccessibilityWin(result)->NewReference();
   return S_OK;
@@ skipping 5071 matching lines @@
   return static_cast<BrowserAccessibilityWin*>(obj);
 }
 
 const BrowserAccessibilityWin*
 ToBrowserAccessibilityWin(const BrowserAccessibility* obj) {
   DCHECK(!obj || obj->IsNative());
   return static_cast<const BrowserAccessibilityWin*>(obj);
 }
 
 }  // namespace content