One accessibility tree per frame.

ui/accessibility/ax_tree_data.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 "ui/accessibility/ax_tree_data.h"
 
 #include <set>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 
 using base::DoubleToString;
 using base::IntToString;
 
 namespace ui {
 
 AXTreeData::AXTreeData()
     : tree_id(-1),
       parent_tree_id(-1),
+      focused_tree_id(-1),
       loaded(false),
       loading_progress(0.0),
       focus_id(-1),
       sel_anchor_object_id(-1),
       sel_anchor_offset(-1),
       sel_focus_object_id(-1),
       sel_focus_offset(-1) {
 }
 
 AXTreeData::AXTreeData(const AXTreeData& other) = default;
 
 AXTreeData::~AXTreeData() {
 }
 
 // Note that this includes an initial space character if nonempty, but
 // that works fine because this is normally printed by AXTree::ToString.
 std::string AXTreeData::ToString() const {
   std::string result;
 
   if (tree_id != -1)
     result += " tree_id=" + IntToString(tree_id);
   if (parent_tree_id != -1)
     result += " parent_tree_id=" + IntToString(parent_tree_id);
+  if (focused_tree_id != -1)
+    result += " focused_tree_id=" + IntToString(focused_tree_id);
 
   if (!url.empty())
     result += " url=" + url;
   if (!title.empty())
     result += " title=" + title;
   if (!mimetype.empty())
     result += " mimetype=" + mimetype;
   if (!doctype.empty())
     result += " doctype=" + doctype;
 
@@ skipping 13 matching lines @@
     result += " sel_focus_object_id=" + IntToString(sel_focus_object_id);
     result += " sel_focus_offset=" + IntToString(sel_focus_offset);
   }
 
   return result;
 }
 
 bool operator==(const AXTreeData& lhs, const AXTreeData& rhs) {
   return (lhs.tree_id == rhs.tree_id &&
           lhs.parent_tree_id == rhs.parent_tree_id &&
+          lhs.focused_tree_id == rhs.focused_tree_id &&
           lhs.url == rhs.url &&
           lhs.title == rhs.title &&
           lhs.mimetype == rhs.mimetype &&
           lhs.doctype == rhs.doctype &&
           lhs.loaded == rhs.loaded &&
           lhs.loading_progress == rhs.loading_progress &&
           lhs.focus_id == rhs.focus_id &&
           lhs.sel_anchor_object_id == rhs.sel_anchor_object_id &&
           lhs.sel_anchor_offset == rhs.sel_anchor_offset &&
           lhs.sel_focus_object_id == rhs.sel_focus_object_id &&
           lhs.sel_focus_offset == rhs.sel_focus_offset);
 }
 
 bool operator!=(const AXTreeData& lhs, const AXTreeData& rhs) {
   return !(lhs == rhs);
 }
 
 }  // namespace ui