Re-land: Initial skeleton of Accessibility Object Model Phase 1

third_party/WebKit/Source/core/dom/AccessibleNode.cpp

+// Copyright 2017 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 "core/dom/AccessibleNode.h"
+
+#include "core/dom/AXObjectCache.h"
+#include "core/dom/Element.h"
+#include "core/dom/QualifiedName.h"
+#include "core/frame/Settings.h"
+
+namespace blink {
+
+AccessibleNode::AccessibleNode(Element* element) : m_element(element) {
+  DCHECK(RuntimeEnabledFeatures::accessibilityObjectModelEnabled());
+}
+
+AccessibleNode::~AccessibleNode() {}
+
+// static
+const AtomicString& AccessibleNode::getProperty(Element* element,
+                                                AOMStringProperty property) {
+  if (!element)
+    return nullAtom;
+
+  if (AccessibleNode* accessibleNode = element->existingAccessibleNode()) {
+    for (const auto& item : accessibleNode->m_stringProperties) {
+      if (item.first == property)
+        return item.second;
+    }
+  }
+
+  // Fall back on the equivalent ARIA attribute.
+  switch (property) {
+    case AOMStringProperty::kRole:
+      return element->getAttribute(HTMLNames::roleAttr);
+    case AOMStringProperty::kLabel:
+      return element->getAttribute(HTMLNames::aria_labelAttr);
+    default:
+      NOTREACHED();
+      return nullAtom;
+  }
+}
+
+AtomicString AccessibleNode::role() const {
+  return getProperty(m_element, AOMStringProperty::kRole);
+}
+
+void AccessibleNode::setRole(const AtomicString& role) {
+  setStringProperty(AOMStringProperty::kRole, role);
+
+  // TODO(dmazzoni): Make a cleaner API for this rather than pretending
+  // the DOM attribute changed.
+  if (AXObjectCache* cache = m_element->document().axObjectCache())
+    cache->handleAttributeChanged(HTMLNames::roleAttr, m_element);
+}
+
+AtomicString AccessibleNode::label() const {
+  return getProperty(m_element, AOMStringProperty::kLabel);
+}
+
+void AccessibleNode::setLabel(const AtomicString& label) {
+  setStringProperty(AOMStringProperty::kLabel, label);
+
+  if (AXObjectCache* cache = m_element->document().axObjectCache())
+    cache->handleAttributeChanged(HTMLNames::aria_labelAttr, m_element);
+}
+
+void AccessibleNode::setStringProperty(AOMStringProperty property,
+                                       const AtomicString& value) {
+  for (auto& item : m_stringProperties) {
+    if (item.first == property) {
+      item.second = value;
+      return;
+    }
+  }
+
+  m_stringProperties.push_back(std::make_pair(property, value));
+}
+
+DEFINE_TRACE(AccessibleNode) {
+  visitor->trace(m_element);
+}
+
+}  // namespace blink