a11y: Exclude children of nested keyboard accessible controls from a11y tree.

ui/views/accessibility/native_view_accessibility_base.cc

 // Copyright (c) 2013 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/native_view_accessibility_base.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/events/event_utils.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/controls/native/native_view_host.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace views {
 
+namespace {
+
+bool IsAccessibilityFocusableWhenEnabled(View* view) {
+  return view->focus_behavior() != View::FocusBehavior::NEVER &&
+         view->IsDrawn();
+}
+
+// Used to determine if a View should be ignored by accessibility clients by
+// being a non-keyboard-focusable child of a keyboard-focusable ancestor. E.g.,
+// LabelButtons contain Labels, but a11y should just show that there's a button.
+bool IsViewUnfocusableChildOfFocusableAncestor(View* view) {
+  if (IsAccessibilityFocusableWhenEnabled(view))
+    return false;
+
+  while (view->parent()) {
+    view = view->parent();
+    if (IsAccessibilityFocusableWhenEnabled(view))
+      return true;
+  }
+  return false;
+}
+
+}  // namespace
+
 NativeViewAccessibilityBase::NativeViewAccessibilityBase(View* view)
     : view_(view),
       parent_widget_(nullptr),
       ax_node_(ui::AXPlatformNode::Create(this)) {
   DCHECK(ax_node_);
 }
 
 NativeViewAccessibilityBase::~NativeViewAccessibilityBase() {
   ax_node_->Destroy();
   if (parent_widget_)
@@ skipping 31 matching lines @@
 
   if (view_->IsAccessibilityFocusable())
     data_.AddState(ui::AX_STATE_FOCUSABLE);
 
   if (!view_->enabled())
     data_.AddState(ui::AX_STATE_DISABLED);
 
   if (!view_->IsDrawn())
     data_.AddState(ui::AX_STATE_INVISIBLE);
 
+  // Make sure this element is excluded from the a11y tree if there's a
+  // focusable parent. All keyboard focusable elements should be leaf nodes.
+  // Exceptions to this rule will themselves be accessibility focusable.
+  if (IsViewUnfocusableChildOfFocusableAncestor(view_))
+    data_.role = ui::AX_ROLE_IGNORED;
   return data_;
 }
 
 int NativeViewAccessibilityBase::GetChildCount() {
   int child_count = view_->child_count();
 
   std::vector<Widget*> child_widgets;
   PopulateChildWidgetVector(&child_widgets);
   child_count += child_widgets.size();
 
@@ skipping 141 matching lines @@
               child_widget_platform_node->GetDelegate());
       if (child_widget_view_accessibility->parent_widget() != widget)
         child_widget_view_accessibility->SetParentWidget(widget);
     }
 
     result_child_widgets->push_back(child_widget);
   }
 }
 
 }  // namespace views