Added a class acting as a fake caret for accessibility.

ui/accessibility/platform/ax_platform_node_win.cc

 // Copyright 2015 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 <atlbase.h>
 #include <atlcom.h>
 #include <limits.h>
 #include <oleacc.h>
 #include <stdint.h>
 
@@ skipping 1022 matching lines @@
 int AXPlatformNodeWin::MSAARole() {
   switch (GetData().role) {
     case ui::AX_ROLE_ALERT:
       return ROLE_SYSTEM_ALERT;
     case ui::AX_ROLE_APPLICATION:
       return ROLE_SYSTEM_APPLICATION;
     case ui::AX_ROLE_BUTTON_DROP_DOWN:
       return ROLE_SYSTEM_BUTTONDROPDOWN;
     case ui::AX_ROLE_POP_UP_BUTTON:
       return ROLE_SYSTEM_BUTTONMENU;
+    case ui::AX_ROLE_CARET:
+      return ROLE_SYSTEM_CARET;
     case ui::AX_ROLE_CHECK_BOX:
       return ROLE_SYSTEM_CHECKBUTTON;
     case ui::AX_ROLE_COMBO_BOX:
       return ROLE_SYSTEM_COMBOBOX;
     case ui::AX_ROLE_DIALOG:
       return ROLE_SYSTEM_DIALOG;
     case ui::AX_ROLE_GROUP:
       return ROLE_SYSTEM_GROUPING;
     case ui::AX_ROLE_IMAGE:
       return ROLE_SYSTEM_GRAPHIC;
@@ skipping 237 matching lines @@
 
   AXPlatformNodeBase* base =
       FromNativeViewAccessible(node->GetNativeViewAccessible());
   if (base && !IsDescendant(base))
     base = nullptr;
 
   return static_cast<AXPlatformNodeWin*>(base);
 }
 
 }  // namespace ui