Handling of different types of empty alt

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 466 matching lines @@
   HRESULT result = target->GetStringAttributeAsBstr(ui::AX_ATTR_NAME, name);
   if (FAILED(result) && MSAARole() == ROLE_SYSTEM_DOCUMENT && GetParent()) {
     // Hack: Some versions of JAWS crash if they get an empty name on
     // a document that's the child of an iframe, so always return a
     // nonempty string for this role.  https://crbug.com/583057
     base::string16 str = L" ";
 
     *name = SysAllocString(str.c_str());
     DCHECK(*name);
   }
+
   return result;
 }
 
 STDMETHODIMP AXPlatformNodeWin::get_accParent(
     IDispatch** disp_parent) {
   COM_OBJECT_VALIDATE_1_ARG(disp_parent);
   *disp_parent = GetParent();
   if (*disp_parent) {
     (*disp_parent)->AddRef();
     return S_OK;
@@ skipping 703 matching lines @@
 }
 
 HRESULT AXPlatformNodeWin::GetStringAttributeAsBstr(
     ui::AXStringAttribute attribute,
     BSTR* value_bstr) const {
   base::string16 str;
 
   if (!GetString16Attribute(attribute, &str))
     return S_FALSE;
 
-  if (str.empty())
-    return S_FALSE;
-
   *value_bstr = SysAllocString(str.c_str());
   DCHECK(*value_bstr);
 
   return S_OK;
 }
 
 void AXPlatformNodeWin::AddAlertTarget() {
   g_alert_targets.Get().insert(this);
 }
 
@@ skipping 69 matching lines @@
 
   AXPlatformNodeBase* base =
       FromNativeViewAccessible(node->GetNativeViewAccessible());
   if (base && !IsDescendant(base))
     base = nullptr;
 
   return static_cast<AXPlatformNodeWin*>(base);
 }
 
 }  // namespace ui