A11y: Add/refactor methods for manipulating bitfields on AXNodeData.

ui/views/accessibility/ax_view_obj_wrapper.cc

 // Copyright 2014 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 "ui/views/accessibility/ax_view_obj_wrapper.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_action_data.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/events/event_utils.h"
@@ skipping 28 matching lines @@
     if (!view_->child_at(i)->visible())
       continue;
 
     AXAuraObjWrapper* child =
         AXAuraObjCache::GetInstance()->GetOrCreate(view_->child_at(i));
     out_children->push_back(child);
   }
 }
 
 void AXViewObjWrapper::Serialize(ui::AXNodeData* out_node_data) {
-  out_node_data->state = 0;

[sky, 2017/05/08 15:56:27]

How come the new code doesn't need a ClearState() or something? Is it assumed
that Serialize() is called with the state set to 0 already?

[Patti Lor, 2017/05/09 06:03:40]

The current AXNodeData class initialises its |state| member to be 0xffffff,
which was an invalid state (see
https://codereview.chromium.org/2860883003/#msg28 - Dominic's comment - for the
reason if you're interested). This patch is changing it so that it is inited to
0x0 instead, so this is fine :)

   view_->GetAccessibleNodeData(out_node_data);
 
   out_node_data->id = GetID();
 
   if (view_->IsAccessibilityFocusable())
-    out_node_data->state |= 1 << ui::AX_STATE_FOCUSABLE;
+    out_node_data->AddState(ui::AX_STATE_FOCUSABLE);
   if (!view_->visible())
-    out_node_data->state |= 1 << ui::AX_STATE_INVISIBLE;
+    out_node_data->AddState(ui::AX_STATE_INVISIBLE);
 
   out_node_data->location = gfx::RectF(view_->GetBoundsInScreen());
 }
 
 int32_t AXViewObjWrapper::GetID() {
   return AXAuraObjCache::GetInstance()->GetID(view_);
 }
 
 bool AXViewObjWrapper::HandleAccessibleAction(const ui::AXActionData& action) {
   return view_->HandleAccessibleAction(action);
 }
 
 }  // namespace views