Reland of name AXObject to AXObjectImpl in modules/ and web/

third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp b/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..39bfb8dde2daae98e48f5f9ac9f885e932f03086
--- /dev/null
+++ b/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp
@@ -0,0 +1,1884 @@
+/*
+ * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "modules/accessibility/AXObjectImpl.h"
+
+#include "SkMatrix44.h"
+#include "core/InputTypeNames.h"
+#include "core/css/resolver/StyleResolver.h"
+#include "core/dom/AccessibleNode.h"
+#include "core/dom/DocumentUserGestureToken.h"
+#include "core/editing/EditingUtilities.h"
+#include "core/editing/VisibleUnits.h"
+#include "core/frame/FrameView.h"
+#include "core/frame/LocalFrame.h"
+#include "core/frame/Settings.h"
+#include "core/html/HTMLDialogElement.h"
+#include "core/html/HTMLFrameOwnerElement.h"
+#include "core/html/HTMLInputElement.h"
+#include "core/html/parser/HTMLParserIdioms.h"
+#include "core/layout/LayoutBoxModelObject.h"
+#include "modules/accessibility/AXObjectCacheImpl.h"
+#include "platform/UserGestureIndicator.h"
+#include "platform/text/PlatformLocale.h"
+#include "platform/wtf/HashSet.h"
+#include "platform/wtf/StdLibExtras.h"
+#include "platform/wtf/text/WTFString.h"
+
+using blink::WebLocalizedString;
+
+namespace blink {
+
+using namespace HTMLNames;
+
+namespace {
+typedef HashMap<String, AccessibilityRole, CaseFoldingHash> ARIARoleMap;
+typedef HashSet<String, CaseFoldingHash> ARIAWidgetSet;
+
+struct RoleEntry {
+  const char* aria_role;
+  AccessibilityRole webcore_role;
+};
+
+const RoleEntry kRoles[] = {{"alert", kAlertRole},
+                            {"alertdialog", kAlertDialogRole},
+                            {"application", kApplicationRole},
+                            {"article", kArticleRole},
+                            {"banner", kBannerRole},
+                            {"button", kButtonRole},
+                            {"cell", kCellRole},
+                            {"checkbox", kCheckBoxRole},
+                            {"columnheader", kColumnHeaderRole},
+                            {"combobox", kComboBoxRole},
+                            {"complementary", kComplementaryRole},
+                            {"contentinfo", kContentInfoRole},
+                            {"definition", kDefinitionRole},
+                            {"dialog", kDialogRole},
+                            {"directory", kDirectoryRole},
+                            {"document", kDocumentRole},
+                            {"feed", kFeedRole},
+                            {"figure", kFigureRole},
+                            {"form", kFormRole},
+                            {"grid", kGridRole},
+                            {"gridcell", kCellRole},
+                            {"group", kGroupRole},
+                            {"heading", kHeadingRole},
+                            {"img", kImageRole},
+                            {"link", kLinkRole},
+                            {"list", kListRole},
+                            {"listbox", kListBoxRole},
+                            {"listitem", kListItemRole},
+                            {"log", kLogRole},
+                            {"main", kMainRole},
+                            {"marquee", kMarqueeRole},
+                            {"math", kMathRole},
+                            {"menu", kMenuRole},
+                            {"menubar", kMenuBarRole},
+                            {"menuitem", kMenuItemRole},
+                            {"menuitemcheckbox", kMenuItemCheckBoxRole},
+                            {"menuitemradio", kMenuItemRadioRole},
+                            {"navigation", kNavigationRole},
+                            {"none", kNoneRole},
+                            {"note", kNoteRole},
+                            {"option", kListBoxOptionRole},
+                            {"presentation", kPresentationalRole},
+                            {"progressbar", kProgressIndicatorRole},
+                            {"radio", kRadioButtonRole},
+                            {"radiogroup", kRadioGroupRole},
+                            {"region", kRegionRole},
+                            {"row", kRowRole},
+                            {"rowheader", kRowHeaderRole},
+                            {"scrollbar", kScrollBarRole},
+                            {"search", kSearchRole},
+                            {"searchbox", kSearchBoxRole},
+                            {"separator", kSplitterRole},
+                            {"slider", kSliderRole},
+                            {"spinbutton", kSpinButtonRole},
+                            {"status", kStatusRole},
+                            {"switch", kSwitchRole},
+                            {"tab", kTabRole},
+                            {"table", kTableRole},
+                            {"tablist", kTabListRole},
+                            {"tabpanel", kTabPanelRole},
+                            {"term", kTermRole},
+                            {"text", kStaticTextRole},
+                            {"textbox", kTextFieldRole},
+                            {"timer", kTimerRole},
+                            {"toolbar", kToolbarRole},
+                            {"tooltip", kUserInterfaceTooltipRole},
+                            {"tree", kTreeRole},
+                            {"treegrid", kTreeGridRole},
+                            {"treeitem", kTreeItemRole}};
+
+struct InternalRoleEntry {
+  AccessibilityRole webcore_role;
+  const char* internal_role_name;
+};
+
+const InternalRoleEntry kInternalRoles[] = {
+    {kUnknownRole, "Unknown"},
+    {kAbbrRole, "Abbr"},
+    {kAlertDialogRole, "AlertDialog"},
+    {kAlertRole, "Alert"},
+    {kAnchorRole, "Anchor"},
+    {kAnnotationRole, "Annotation"},
+    {kApplicationRole, "Application"},
+    {kArticleRole, "Article"},
+    {kAudioRole, "Audio"},
+    {kBannerRole, "Banner"},
+    {kBlockquoteRole, "Blockquote"},
+    // TODO(nektar): Delete busy_indicator role. It's used nowhere.
+    {kBusyIndicatorRole, "BusyIndicator"},
+    {kButtonRole, "Button"},
+    {kCanvasRole, "Canvas"},
+    {kCaptionRole, "Caption"},
+    {kCellRole, "Cell"},
+    {kCheckBoxRole, "CheckBox"},
+    {kColorWellRole, "ColorWell"},
+    {kColumnHeaderRole, "ColumnHeader"},
+    {kColumnRole, "Column"},
+    {kComboBoxRole, "ComboBox"},
+    {kComplementaryRole, "Complementary"},
+    {kContentInfoRole, "ContentInfo"},
+    {kDateRole, "Date"},
+    {kDateTimeRole, "DateTime"},
+    {kDefinitionRole, "Definition"},
+    {kDescriptionListDetailRole, "DescriptionListDetail"},
+    {kDescriptionListRole, "DescriptionList"},
+    {kDescriptionListTermRole, "DescriptionListTerm"},
+    {kDetailsRole, "Details"},
+    {kDialogRole, "Dialog"},
+    {kDirectoryRole, "Directory"},
+    {kDisclosureTriangleRole, "DisclosureTriangle"},
+    {kDivRole, "Div"},
+    {kDocumentRole, "Document"},
+    {kEmbeddedObjectRole, "EmbeddedObject"},
+    {kFeedRole, "feed"},
+    {kFigcaptionRole, "Figcaption"},
+    {kFigureRole, "Figure"},
+    {kFooterRole, "Footer"},
+    {kFormRole, "Form"},
+    {kGridRole, "Grid"},
+    {kGroupRole, "Group"},
+    {kHeadingRole, "Heading"},
+    {kIframePresentationalRole, "IframePresentational"},
+    {kIframeRole, "Iframe"},
+    {kIgnoredRole, "Ignored"},
+    {kImageMapLinkRole, "ImageMapLink"},
+    {kImageMapRole, "ImageMap"},
+    {kImageRole, "Image"},
+    {kInlineTextBoxRole, "InlineTextBox"},
+    {kInputTimeRole, "InputTime"},
+    {kLabelRole, "Label"},
+    {kLegendRole, "Legend"},
+    {kLinkRole, "Link"},
+    {kLineBreakRole, "LineBreak"},
+    {kListBoxOptionRole, "ListBoxOption"},
+    {kListBoxRole, "ListBox"},
+    {kListItemRole, "ListItem"},
+    {kListMarkerRole, "ListMarker"},
+    {kListRole, "List"},
+    {kLogRole, "Log"},
+    {kMainRole, "Main"},
+    {kMarkRole, "Mark"},
+    {kMarqueeRole, "Marquee"},
+    {kMathRole, "Math"},
+    {kMenuBarRole, "MenuBar"},
+    {kMenuButtonRole, "MenuButton"},
+    {kMenuItemRole, "MenuItem"},
+    {kMenuItemCheckBoxRole, "MenuItemCheckBox"},
+    {kMenuItemRadioRole, "MenuItemRadio"},
+    {kMenuListOptionRole, "MenuListOption"},
+    {kMenuListPopupRole, "MenuListPopup"},
+    {kMenuRole, "Menu"},
+    {kMeterRole, "Meter"},
+    {kNavigationRole, "Navigation"},
+    {kNoneRole, "None"},
+    {kNoteRole, "Note"},
+    {kOutlineRole, "Outline"},
+    {kParagraphRole, "Paragraph"},
+    {kPopUpButtonRole, "PopUpButton"},
+    {kPreRole, "Pre"},
+    {kPresentationalRole, "Presentational"},
+    {kProgressIndicatorRole, "ProgressIndicator"},
+    {kRadioButtonRole, "RadioButton"},
+    {kRadioGroupRole, "RadioGroup"},
+    {kRegionRole, "Region"},
+    {kRootWebAreaRole, "RootWebArea"},
+    {kRowHeaderRole, "RowHeader"},
+    {kRowRole, "Row"},
+    {kRubyRole, "Ruby"},
+    {kRulerRole, "Ruler"},
+    {kSVGRootRole, "SVGRoot"},
+    {kScrollAreaRole, "ScrollArea"},
+    {kScrollBarRole, "ScrollBar"},
+    {kSeamlessWebAreaRole, "SeamlessWebArea"},
+    {kSearchRole, "Search"},
+    {kSearchBoxRole, "SearchBox"},
+    {kSliderRole, "Slider"},
+    {kSliderThumbRole, "SliderThumb"},
+    {kSpinButtonPartRole, "SpinButtonPart"},
+    {kSpinButtonRole, "SpinButton"},
+    {kSplitterRole, "Splitter"},
+    {kStaticTextRole, "StaticText"},
+    {kStatusRole, "Status"},
+    {kSwitchRole, "Switch"},
+    {kTabGroupRole, "TabGroup"},
+    {kTabListRole, "TabList"},
+    {kTabPanelRole, "TabPanel"},
+    {kTabRole, "Tab"},
+    {kTableHeaderContainerRole, "TableHeaderContainer"},
+    {kTableRole, "Table"},
+    {kTermRole, "Term"},
+    {kTextFieldRole, "TextField"},
+    {kTimeRole, "Time"},
+    {kTimerRole, "Timer"},
+    {kToggleButtonRole, "ToggleButton"},
+    {kToolbarRole, "Toolbar"},
+    {kTreeGridRole, "TreeGrid"},
+    {kTreeItemRole, "TreeItem"},
+    {kTreeRole, "Tree"},
+    {kUserInterfaceTooltipRole, "UserInterfaceTooltip"},
+    {kVideoRole, "Video"},
+    {kWebAreaRole, "WebArea"},
+    {kWindowRole, "Window"}};
+
+static_assert(WTF_ARRAY_LENGTH(kInternalRoles) == kNumRoles,
+              "Not all internal roles have an entry in internalRoles array");
+
+// Roles which we need to map in the other direction
+const RoleEntry kReverseRoles[] = {
+    {"button", kToggleButtonRole},     {"combobox", kPopUpButtonRole},
+    {"contentinfo", kFooterRole},      {"menuitem", kMenuButtonRole},
+    {"menuitem", kMenuListOptionRole}, {"progressbar", kMeterRole},
+    {"textbox", kTextFieldRole}};
+
+static ARIARoleMap* CreateARIARoleMap() {
+  ARIARoleMap* role_map = new ARIARoleMap;
+
+  for (size_t i = 0; i < WTF_ARRAY_LENGTH(kRoles); ++i)
+    role_map->Set(String(kRoles[i].aria_role), kRoles[i].webcore_role);
+  return role_map;
+}
+
+static Vector<AtomicString>* CreateRoleNameVector() {
+  Vector<AtomicString>* role_name_vector = new Vector<AtomicString>(kNumRoles);
+  for (int i = 0; i < kNumRoles; i++)
+    (*role_name_vector)[i] = g_null_atom;
+
+  for (size_t i = 0; i < WTF_ARRAY_LENGTH(kRoles); ++i) {
+    (*role_name_vector)[kRoles[i].webcore_role] =
+        AtomicString(kRoles[i].aria_role);
+  }
+
+  for (size_t i = 0; i < WTF_ARRAY_LENGTH(kReverseRoles); ++i) {
+    (*role_name_vector)[kReverseRoles[i].webcore_role] =
+        AtomicString(kReverseRoles[i].aria_role);
+  }
+
+  return role_name_vector;
+}
+
+static Vector<AtomicString>* CreateInternalRoleNameVector() {
+  Vector<AtomicString>* internal_role_name_vector =
+      new Vector<AtomicString>(kNumRoles);
+  for (size_t i = 0; i < WTF_ARRAY_LENGTH(kInternalRoles); i++) {
+    (*internal_role_name_vector)[kInternalRoles[i].webcore_role] =
+        AtomicString(kInternalRoles[i].internal_role_name);
+  }
+
+  return internal_role_name_vector;
+}
+
+const char* g_aria_widgets[] = {
+    // From http://www.w3.org/TR/wai-aria/roles#widget_roles
+    "alert", "alertdialog", "button", "checkbox", "dialog", "gridcell", "link",
+    "log", "marquee", "menuitem", "menuitemcheckbox", "menuitemradio", "option",
+    "progressbar", "radio", "scrollbar", "slider", "spinbutton", "status",
+    "tab", "tabpanel", "textbox", "timer", "tooltip", "treeitem",
+    // Composite user interface widgets.
+    // This list is also from the w3.org site referenced above.
+    "combobox", "grid", "listbox", "menu", "menubar", "radiogroup", "tablist",
+    "tree", "treegrid"};
+
+static ARIAWidgetSet* CreateARIARoleWidgetSet() {
+  ARIAWidgetSet* widget_set = new HashSet<String, CaseFoldingHash>();
+  for (size_t i = 0; i < WTF_ARRAY_LENGTH(g_aria_widgets); ++i)
+    widget_set->insert(String(g_aria_widgets[i]));
+  return widget_set;
+}
+
+const char* g_aria_interactive_widget_attributes[] = {
+    // These attributes implicitly indicate the given widget is interactive.
+    // From http://www.w3.org/TR/wai-aria/states_and_properties#attrs_widgets
+    "aria-activedescendant", "aria-checked",  "aria-controls",
+    "aria-disabled",  // If it's disabled, it can be made interactive.
+    "aria-expanded",         "aria-haspopup", "aria-multiselectable",
+    "aria-pressed",          "aria-required", "aria-selected"};
+
+HTMLDialogElement* GetActiveDialogElement(Node* node) {
+  return node->GetDocument().ActiveModalDialog();
+}
+
+}  // namespace
+
+unsigned AXObjectImpl::number_of_live_ax_objects_ = 0;
+
+AXObjectImpl::AXObjectImpl(AXObjectCacheImpl& ax_object_cache)
+    : id_(0),
+      have_children_(false),
+      role_(kUnknownRole),
+      last_known_is_ignored_value_(kDefaultBehavior),
+      explicit_container_id_(0),
+      parent_(nullptr),
+      last_modification_count_(-1),
+      cached_is_ignored_(false),
+      cached_is_inert_or_aria_hidden_(false),
+      cached_is_descendant_of_leaf_node_(false),
+      cached_is_descendant_of_disabled_node_(false),
+      cached_has_inherited_presentational_role_(false),
+      cached_is_presentational_child_(false),
+      cached_ancestor_exposes_active_descendant_(false),
+      cached_live_region_root_(nullptr),
+      ax_object_cache_(&ax_object_cache) {
+  ++number_of_live_ax_objects_;
+}
+
+AXObjectImpl::~AXObjectImpl() {
+  DCHECK(IsDetached());
+  --number_of_live_ax_objects_;
+}
+
+void AXObjectImpl::Detach() {
+  // Clear any children and call detachFromParent on them so that
+  // no children are left with dangling pointers to their parent.
+  ClearChildren();
+
+  ax_object_cache_ = nullptr;
+}
+
+bool AXObjectImpl::IsDetached() const {
+  return !ax_object_cache_;
+}
+
+const AtomicString& AXObjectImpl::GetAOMPropertyOrARIAAttribute(
+    AOMStringProperty property) const {
+  Node* node = this->GetNode();
+  if (!node || !node->IsElementNode())
+    return g_null_atom;
+
+  return AccessibleNode::GetPropertyOrARIAAttribute(ToElement(node), property);
+}
+
+bool AXObjectImpl::IsARIATextControl() const {
+  return AriaRoleAttribute() == kTextFieldRole ||
+         AriaRoleAttribute() == kSearchBoxRole ||
+         AriaRoleAttribute() == kComboBoxRole;
+}
+
+bool AXObjectImpl::IsButton() const {
+  AccessibilityRole role = RoleValue();
+
+  return role == kButtonRole || role == kPopUpButtonRole ||
+         role == kToggleButtonRole;
+}
+
+bool AXObjectImpl::IsCheckable() const {
+  switch (RoleValue()) {
+    case kCheckBoxRole:
+    case kMenuItemCheckBoxRole:
+    case kMenuItemRadioRole:
+    case kRadioButtonRole:
+    case kSwitchRole:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// Why this is here instead of AXNodeObject:
+// Because an AXMenuListOption (<option>) can
+// have an ARIA role of menuitemcheckbox/menuitemradio
+// yet does not inherit from AXNodeObject
+AccessibilityButtonState AXObjectImpl::CheckedState() const {
+  if (!IsCheckable())
+    return kButtonStateOff;
+
+  const AtomicString& checkedAttribute =
+      GetAOMPropertyOrARIAAttribute(AOMStringProperty::kChecked);
+  if (checkedAttribute) {
+    if (EqualIgnoringASCIICase(checkedAttribute, "true"))
+      return kButtonStateOn;
+
+    if (EqualIgnoringASCIICase(checkedAttribute, "mixed")) {
+      // Only checkboxes and radios should support the mixed state.
+      const AccessibilityRole role = RoleValue();
+      if (role == kCheckBoxRole || role == kMenuItemCheckBoxRole ||
+          role == kRadioButtonRole || role == kMenuItemRadioRole)
+        return kButtonStateMixed;
+    }
+
+    return kButtonStateOff;
+  }
+
+  const Node* node = this->GetNode();
+  if (!node)
+    return kButtonStateOff;
+
+  if (IsNativeInputInMixedState(node))
+    return kButtonStateMixed;
+
+  if (isHTMLInputElement(*node) &&
+      toHTMLInputElement(*node).ShouldAppearChecked()) {
+    return kButtonStateOn;
+  }
+
+  return kButtonStateOff;
+}
+
+bool AXObjectImpl::IsNativeInputInMixedState(const Node* node) {
+  if (!isHTMLInputElement(node))
+    return false;
+
+  const HTMLInputElement* input = toHTMLInputElement(node);
+  const auto inputType = input->type();
+  if (inputType != InputTypeNames::checkbox &&
+      inputType != InputTypeNames::radio)
+    return false;
+  return input->ShouldAppearIndeterminate();
+}
+
+bool AXObjectImpl::IsLandmarkRelated() const {
+  switch (RoleValue()) {
+    case kApplicationRole:
+    case kArticleRole:
+    case kBannerRole:
+    case kComplementaryRole:
+    case kContentInfoRole:
+    case kFooterRole:
+    case kFormRole:
+    case kMainRole:
+    case kNavigationRole:
+    case kRegionRole:
+    case kSearchRole:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool AXObjectImpl::IsMenuRelated() const {
+  switch (RoleValue()) {
+    case kMenuRole:
+    case kMenuBarRole:
+    case kMenuButtonRole:
+    case kMenuItemRole:
+    case kMenuItemCheckBoxRole:
+    case kMenuItemRadioRole:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool AXObjectImpl::IsPasswordFieldAndShouldHideValue() const {
+  Settings* settings = GetDocument()->GetSettings();
+  if (!settings || settings->GetAccessibilityPasswordValuesEnabled())
+    return false;
+
+  return IsPasswordField();
+}
+
+bool AXObjectImpl::IsClickable() const {
+  switch (RoleValue()) {
+    case kButtonRole:
+    case kCheckBoxRole:
+    case kColorWellRole:
+    case kComboBoxRole:
+    case kImageMapLinkRole:
+    case kLinkRole:
+    case kListBoxOptionRole:
+    case kMenuButtonRole:
+    case kPopUpButtonRole:
+    case kRadioButtonRole:
+    case kSpinButtonRole:
+    case kTabRole:
+    case kTextFieldRole:
+    case kToggleButtonRole:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool AXObjectImpl::AccessibilityIsIgnored() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_is_ignored_;
+}
+
+void AXObjectImpl::UpdateCachedAttributeValuesIfNeeded() const {
+  if (IsDetached())
+    return;
+
+  AXObjectCacheImpl& cache = AxObjectCache();
+
+  if (cache.ModificationCount() == last_modification_count_)
+    return;
+
+  last_modification_count_ = cache.ModificationCount();
+  cached_background_color_ = ComputeBackgroundColor();
+  cached_is_inert_or_aria_hidden_ = ComputeIsInertOrAriaHidden();
+  cached_is_descendant_of_leaf_node_ = (LeafNodeAncestor() != 0);
+  cached_is_descendant_of_disabled_node_ = (DisabledAncestor() != 0);
+  cached_has_inherited_presentational_role_ =
+      (InheritsPresentationalRoleFrom() != 0);
+  cached_is_presentational_child_ =
+      (AncestorForWhichThisIsAPresentationalChild() != 0);
+  cached_is_ignored_ = ComputeAccessibilityIsIgnored();
+  cached_live_region_root_ =
+      IsLiveRegion()
+          ? const_cast<AXObjectImpl*>(this)
+          : (ParentObjectIfExists() ? ParentObjectIfExists()->LiveRegionRoot()
+                                    : 0);
+  cached_ancestor_exposes_active_descendant_ =
+      ComputeAncestorExposesActiveDescendant();
+}
+
+bool AXObjectImpl::AccessibilityIsIgnoredByDefault(
+    IgnoredReasons* ignored_reasons) const {
+  return DefaultObjectInclusion(ignored_reasons) == kIgnoreObject;
+}
+
+AXObjectInclusion AXObjectImpl::AccessibilityPlatformIncludesObject() const {
+  if (IsMenuListPopup() || IsMenuListOption())
+    return kIncludeObject;
+
+  return kDefaultBehavior;
+}
+
+AXObjectInclusion AXObjectImpl::DefaultObjectInclusion(
+    IgnoredReasons* ignored_reasons) const {
+  if (IsInertOrAriaHidden()) {
+    if (ignored_reasons)
+      ComputeIsInertOrAriaHidden(ignored_reasons);
+    return kIgnoreObject;
+  }
+
+  if (IsPresentationalChild()) {
+    if (ignored_reasons) {
+      AXObjectImpl* ancestor = AncestorForWhichThisIsAPresentationalChild();
+      ignored_reasons->push_back(
+          IgnoredReason(kAXAncestorDisallowsChild, ancestor));
+    }
+    return kIgnoreObject;
+  }
+
+  return AccessibilityPlatformIncludesObject();
+}
+
+bool AXObjectImpl::IsInertOrAriaHidden() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_is_inert_or_aria_hidden_;
+}
+
+bool AXObjectImpl::ComputeIsInertOrAriaHidden(
+    IgnoredReasons* ignored_reasons) const {
+  if (GetNode()) {
+    if (GetNode()->IsInert()) {
+      if (ignored_reasons) {
+        HTMLDialogElement* dialog = GetActiveDialogElement(GetNode());
+        if (dialog) {
+          AXObjectImpl* dialog_object = AxObjectCache().GetOrCreate(dialog);
+          if (dialog_object) {
+            ignored_reasons->push_back(
+                IgnoredReason(kAXActiveModalDialog, dialog_object));
+          } else {
+            ignored_reasons->push_back(IgnoredReason(kAXInert));
+          }
+        } else {
+          // TODO(aboxhall): handle inert attribute if it eventuates
+          ignored_reasons->push_back(IgnoredReason(kAXInert));
+        }
+      }
+      return true;
+    }
+  } else {
+    AXObjectImpl* parent = ParentObject();
+    if (parent && parent->IsInertOrAriaHidden()) {
+      if (ignored_reasons)
+        parent->ComputeIsInertOrAriaHidden(ignored_reasons);
+      return true;
+    }
+  }
+
+  const AXObjectImpl* hidden_root = AriaHiddenRoot();
+  if (hidden_root) {
+    if (ignored_reasons) {
+      if (hidden_root == this) {
+        ignored_reasons->push_back(IgnoredReason(kAXAriaHidden));
+      } else {
+        ignored_reasons->push_back(
+            IgnoredReason(kAXAriaHiddenRoot, hidden_root));
+      }
+    }
+    return true;
+  }
+
+  return false;
+}
+
+bool AXObjectImpl::IsDescendantOfLeafNode() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_is_descendant_of_leaf_node_;
+}
+
+AXObjectImpl* AXObjectImpl::LeafNodeAncestor() const {
+  if (AXObjectImpl* parent = ParentObject()) {
+    if (!parent->CanHaveChildren())
+      return parent;
+
+    return parent->LeafNodeAncestor();
+  }
+
+  return 0;
+}
+
+const AXObjectImpl* AXObjectImpl::AriaHiddenRoot() const {
+  for (const AXObjectImpl* object = this; object;
+       object = object->ParentObject()) {
+    if (EqualIgnoringASCIICase(object->GetAttribute(aria_hiddenAttr), "true"))
+      return object;
+  }
+
+  return 0;
+}
+
+bool AXObjectImpl::IsDescendantOfDisabledNode() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_is_descendant_of_disabled_node_;
+}
+
+const AXObjectImpl* AXObjectImpl::DisabledAncestor() const {
+  const AtomicString& disabled = GetAttribute(aria_disabledAttr);
+  if (EqualIgnoringASCIICase(disabled, "true"))
+    return this;
+  if (EqualIgnoringASCIICase(disabled, "false"))
+    return 0;
+
+  if (AXObjectImpl* parent = ParentObject())
+    return parent->DisabledAncestor();
+
+  return 0;
+}
+
+bool AXObjectImpl::LastKnownIsIgnoredValue() {
+  if (last_known_is_ignored_value_ == kDefaultBehavior) {
+    last_known_is_ignored_value_ =
+        AccessibilityIsIgnored() ? kIgnoreObject : kIncludeObject;
+  }
+
+  return last_known_is_ignored_value_ == kIgnoreObject;
+}
+
+void AXObjectImpl::SetLastKnownIsIgnoredValue(bool is_ignored) {
+  last_known_is_ignored_value_ = is_ignored ? kIgnoreObject : kIncludeObject;
+}
+
+bool AXObjectImpl::HasInheritedPresentationalRole() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_has_inherited_presentational_role_;
+}
+
+bool AXObjectImpl::IsPresentationalChild() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_is_presentational_child_;
+}
+
+bool AXObjectImpl::AncestorExposesActiveDescendant() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_ancestor_exposes_active_descendant_;
+}
+
+bool AXObjectImpl::ComputeAncestorExposesActiveDescendant() const {
+  const AXObjectImpl* parent = ParentObjectUnignored();
+  if (!parent)
+    return false;
+
+  if (parent->SupportsActiveDescendant() &&
+      !parent->GetAttribute(aria_activedescendantAttr).IsEmpty()) {
+    return true;
+  }
+
+  return parent->AncestorExposesActiveDescendant();
+}
+
+// Simplify whitespace, but preserve a single leading and trailing whitespace
+// character if it's present.
+// static
+String AXObjectImpl::CollapseWhitespace(const String& str) {
+  StringBuilder result;
+  if (!str.IsEmpty() && IsHTMLSpace<UChar>(str[0]))
+    result.Append(' ');
+  result.Append(str.SimplifyWhiteSpace(IsHTMLSpace<UChar>));
+  if (!str.IsEmpty() && IsHTMLSpace<UChar>(str[str.length() - 1]))
+    result.Append(' ');
+  return result.ToString();
+}
+
+String AXObjectImpl::ComputedName() const {
+  AXNameFrom name_from;
+  AXObjectImpl::AXObjectVector name_objects;
+  return GetName(name_from, &name_objects);
+}
+
+String AXObjectImpl::GetName(AXNameFrom& name_from,
+                             AXObjectImpl::AXObjectVector* name_objects) const {
+  HeapHashSet<Member<const AXObjectImpl>> visited;
+  AXRelatedObjectVector related_objects;
+  String text = TextAlternative(false, false, visited, name_from,
+                                &related_objects, nullptr);
+
+  AccessibilityRole role = RoleValue();
+  if (!GetNode() || (!isHTMLBRElement(GetNode()) && role != kStaticTextRole &&
+                     role != kInlineTextBoxRole))
+    text = CollapseWhitespace(text);
+
+  if (name_objects) {
+    name_objects->clear();
+    for (size_t i = 0; i < related_objects.size(); i++)
+      name_objects->push_back(related_objects[i]->object);
+  }
+
+  return text;
+}
+
+String AXObjectImpl::GetName(NameSources* name_sources) const {
+  AXObjectSet visited;
+  AXNameFrom tmp_name_from;
+  AXRelatedObjectVector tmp_related_objects;
+  String text = TextAlternative(false, false, visited, tmp_name_from,
+                                &tmp_related_objects, name_sources);
+  text = text.SimplifyWhiteSpace(IsHTMLSpace<UChar>);
+  return text;
+}
+
+String AXObjectImpl::RecursiveTextAlternative(
+    const AXObjectImpl& ax_obj,
+    bool in_aria_labelled_by_traversal,
+    AXObjectSet& visited) {
+  if (visited.Contains(&ax_obj) && !in_aria_labelled_by_traversal)
+    return String();
+
+  AXNameFrom tmp_name_from;
+  return ax_obj.TextAlternative(true, in_aria_labelled_by_traversal, visited,
+                                tmp_name_from, nullptr, nullptr);
+}
+
+bool AXObjectImpl::IsHiddenForTextAlternativeCalculation() const {
+  if (EqualIgnoringASCIICase(GetAttribute(aria_hiddenAttr), "false"))
+    return false;
+
+  if (GetLayoutObject())
+    return GetLayoutObject()->Style()->Visibility() != EVisibility::kVisible;
+
+  // This is an obscure corner case: if a node has no LayoutObject, that means
+  // it's not rendered, but we still may be exploring it as part of a text
+  // alternative calculation, for example if it was explicitly referenced by
+  // aria-labelledby. So we need to explicitly call the style resolver to check
+  // whether it's invisible or display:none, rather than relying on the style
+  // cached in the LayoutObject.
+  Document* document = GetDocument();
+  if (!document || !document->GetFrame())
+    return false;
+  if (Node* node = GetNode()) {
+    if (node->isConnected() && node->IsElementNode()) {
+      RefPtr<ComputedStyle> style =
+          document->EnsureStyleResolver().StyleForElement(ToElement(node));
+      return style->Display() == EDisplay::kNone ||
+             style->Visibility() != EVisibility::kVisible;
+    }
+  }
+  return false;
+}
+
+String AXObjectImpl::AriaTextAlternative(bool recursive,
+                                         bool in_aria_labelled_by_traversal,
+                                         AXObjectSet& visited,
+                                         AXNameFrom& name_from,
+                                         AXRelatedObjectVector* related_objects,
+                                         NameSources* name_sources,
+                                         bool* found_text_alternative) const {
+  String text_alternative;
+  bool already_visited = visited.Contains(this);
+  visited.insert(this);
+
+  // Step 2A from: http://www.w3.org/TR/accname-aam-1.1
+  // If you change this logic, update AXNodeObject::nameFromLabelElement, too.
+  if (!in_aria_labelled_by_traversal &&
+      IsHiddenForTextAlternativeCalculation()) {
+    *found_text_alternative = true;
+    return String();
+  }
+
+  // Step 2B from: http://www.w3.org/TR/accname-aam-1.1
+  // If you change this logic, update AXNodeObject::nameFromLabelElement, too.
+  if (!in_aria_labelled_by_traversal && !already_visited) {
+    const QualifiedName& attr =
+        HasAttribute(aria_labeledbyAttr) && !HasAttribute(aria_labelledbyAttr)
+            ? aria_labeledbyAttr
+            : aria_labelledbyAttr;
+    name_from = kAXNameFromRelatedElement;
+    if (name_sources) {
+      name_sources->push_back(NameSource(*found_text_alternative, attr));
+      name_sources->back().type = name_from;
+    }
+
+    const AtomicString& aria_labelledby = GetAttribute(attr);
+    if (!aria_labelledby.IsNull()) {
+      if (name_sources)
+        name_sources->back().attribute_value = aria_labelledby;
+
+      // Operate on a copy of |visited| so that if |nameSources| is not null,
+      // the set of visited objects is preserved unmodified for future
+      // calculations.
+      AXObjectSet visited_copy = visited;
+      text_alternative = TextFromAriaLabelledby(visited_copy, related_objects);
+      if (!text_alternative.IsNull()) {
+        if (name_sources) {
+          NameSource& source = name_sources->back();
+          source.type = name_from;
+          source.related_objects = *related_objects;
+          source.text = text_alternative;
+          *found_text_alternative = true;
+        } else {
+          *found_text_alternative = true;
+          return text_alternative;
+        }
+      } else if (name_sources) {
+        name_sources->back().invalid = true;
+      }
+    }
+  }
+
+  // Step 2C from: http://www.w3.org/TR/accname-aam-1.1
+  // If you change this logic, update AXNodeObject::nameFromLabelElement, too.
+  name_from = kAXNameFromAttribute;
+  if (name_sources) {
+    name_sources->push_back(
+        NameSource(*found_text_alternative, aria_labelAttr));
+    name_sources->back().type = name_from;
+  }
+  const AtomicString& aria_label =
+      GetAOMPropertyOrARIAAttribute(AOMStringProperty::kLabel);
+  if (!aria_label.IsEmpty()) {
+    text_alternative = aria_label;
+
+    if (name_sources) {
+      NameSource& source = name_sources->back();
+      source.text = text_alternative;
+      source.attribute_value = aria_label;
+      *found_text_alternative = true;
+    } else {
+      *found_text_alternative = true;
+      return text_alternative;
+    }
+  }
+
+  return text_alternative;
+}
+
+String AXObjectImpl::TextFromElements(
+    bool in_aria_labelledby_traversal,
+    AXObjectSet& visited,
+    HeapVector<Member<Element>>& elements,
+    AXRelatedObjectVector* related_objects) const {
+  StringBuilder accumulated_text;
+  bool found_valid_element = false;
+  AXRelatedObjectVector local_related_objects;
+
+  for (const auto& element : elements) {
+    AXObjectImpl* ax_element = AxObjectCache().GetOrCreate(element);
+    if (ax_element) {
+      found_valid_element = true;
+
+      String result = RecursiveTextAlternative(
+          *ax_element, in_aria_labelledby_traversal, visited);
+      local_related_objects.push_back(
+          new NameSourceRelatedObject(ax_element, result));
+      if (!result.IsEmpty()) {
+        if (!accumulated_text.IsEmpty())
+          accumulated_text.Append(' ');
+        accumulated_text.Append(result);
+      }
+    }
+  }
+  if (!found_valid_element)
+    return String();
+  if (related_objects)
+    *related_objects = local_related_objects;
+  return accumulated_text.ToString();
+}
+
+void AXObjectImpl::TokenVectorFromAttribute(
+    Vector<String>& tokens,
+    const QualifiedName& attribute) const {
+  Node* node = this->GetNode();
+  if (!node || !node->IsElementNode())
+    return;
+
+  String attribute_value = GetAttribute(attribute).GetString();
+  if (attribute_value.IsEmpty())
+    return;
+
+  attribute_value.SimplifyWhiteSpace();
+  attribute_value.Split(' ', tokens);
+}
+
+void AXObjectImpl::ElementsFromAttribute(HeapVector<Member<Element>>& elements,
+                                         const QualifiedName& attribute) const {
+  Vector<String> ids;
+  TokenVectorFromAttribute(ids, attribute);
+  if (ids.IsEmpty())
+    return;
+
+  TreeScope& scope = GetNode()->GetTreeScope();
+  for (const auto& id : ids) {
+    if (Element* id_element = scope.getElementById(AtomicString(id)))
+      elements.push_back(id_element);
+  }
+}
+
+void AXObjectImpl::AriaLabelledbyElementVector(
+    HeapVector<Member<Element>>& elements) const {
+  // Try both spellings, but prefer aria-labelledby, which is the official spec.
+  ElementsFromAttribute(elements, aria_labelledbyAttr);
+  if (!elements.size())
+    ElementsFromAttribute(elements, aria_labeledbyAttr);
+}
+
+String AXObjectImpl::TextFromAriaLabelledby(
+    AXObjectSet& visited,
+    AXRelatedObjectVector* related_objects) const {
+  HeapVector<Member<Element>> elements;
+  AriaLabelledbyElementVector(elements);
+  return TextFromElements(true, visited, elements, related_objects);
+}
+
+String AXObjectImpl::TextFromAriaDescribedby(
+    AXRelatedObjectVector* related_objects) const {
+  AXObjectSet visited;
+  HeapVector<Member<Element>> elements;
+  ElementsFromAttribute(elements, aria_describedbyAttr);
+  return TextFromElements(true, visited, elements, related_objects);
+}
+
+RGBA32 AXObjectImpl::BackgroundColor() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_background_color_;
+}
+
+AccessibilityOrientation AXObjectImpl::Orientation() const {
+  // In ARIA 1.1, the default value for aria-orientation changed from
+  // horizontal to undefined.
+  return kAccessibilityOrientationUndefined;
+}
+
+AXSupportedAction AXObjectImpl::Action() const {
+  if (!ActionElement())
+    return AXSupportedAction::kNone;
+
+  switch (RoleValue()) {
+    case kButtonRole:
+    case kToggleButtonRole:
+      return AXSupportedAction::kPress;
+    case kTextFieldRole:
+      return AXSupportedAction::kActivate;
+    case kRadioButtonRole:
+      return AXSupportedAction::kSelect;
+    case kCheckBoxRole:
+    case kSwitchRole:
+      return CheckedState() == kButtonStateOff ? AXSupportedAction::kCheck
+                                               : AXSupportedAction::kUncheck;
+    case kLinkRole:
+      return AXSupportedAction::kJump;
+    case kPopUpButtonRole:
+      return AXSupportedAction::kOpen;
+    default:
+      return AXSupportedAction::kClick;
+  }
+}
+
+bool AXObjectImpl::IsMultiline() const {
+  Node* node = this->GetNode();
+  if (!node)
+    return false;
+
+  if (isHTMLTextAreaElement(*node))
+    return true;
+
+  if (HasEditableStyle(*node))
+    return true;
+
+  if (!IsNativeTextControl() && !IsNonNativeTextControl())
+    return false;
+
+  return EqualIgnoringASCIICase(GetAttribute(aria_multilineAttr), "true");
+}
+
+bool AXObjectImpl::AriaPressedIsPresent() const {
+  return !GetAttribute(aria_pressedAttr).IsEmpty();
+}
+
+bool AXObjectImpl::SupportsActiveDescendant() const {
+  // According to the ARIA Spec, all ARIA composite widgets, ARIA text boxes
+  // and ARIA groups should be able to expose an active descendant.
+  // Implicitly, <input> and <textarea> elements should also have this ability.
+  switch (AriaRoleAttribute()) {
+    case kComboBoxRole:
+    case kGridRole:
+    case kGroupRole:
+    case kListBoxRole:
+    case kMenuRole:
+    case kMenuBarRole:
+    case kRadioGroupRole:
+    case kRowRole:
+    case kSearchBoxRole:
+    case kTabListRole:
+    case kTextFieldRole:
+    case kToolbarRole:
+    case kTreeRole:
+    case kTreeGridRole:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool AXObjectImpl::SupportsARIAAttributes() const {
+  return IsLiveRegion() || SupportsARIADragging() || SupportsARIADropping() ||
+         SupportsARIAFlowTo() || SupportsARIAOwns() ||
+         HasAttribute(aria_labelAttr);
+}
+
+bool AXObjectImpl::SupportsRangeValue() const {
+  return IsProgressIndicator() || IsMeter() || IsSlider() || IsScrollbar() ||
+         IsSpinButton();
+}
+
+bool AXObjectImpl::SupportsSetSizeAndPosInSet() const {
+  AXObjectImpl* parent = ParentObject();
+  if (!parent)
+    return false;
+
+  int role = RoleValue();
+  int parent_role = parent->RoleValue();
+
+  if ((role == kListBoxOptionRole && parent_role == kListBoxRole) ||
+      (role == kListItemRole && parent_role == kListRole) ||
+      (role == kMenuItemRole && parent_role == kMenuRole) ||
+      (role == kRadioButtonRole) ||
+      (role == kTabRole && parent_role == kTabListRole) ||
+      (role == kTreeItemRole && parent_role == kTreeRole) ||
+      (role == kTreeItemRole && parent_role == kGroupRole)) {
+    return true;
+  }
+
+  return false;
+}
+
+int AXObjectImpl::IndexInParent() const {
+  if (!ParentObject())
+    return 0;
+
+  const auto& siblings = ParentObject()->Children();
+  int child_count = siblings.size();
+
+  for (int index = 0; index < child_count; ++index) {
+    if (siblings[index].Get() == this) {
+      return index;
+    }
+  }
+  return 0;
+}
+
+bool AXObjectImpl::IsLiveRegion() const {
+  const AtomicString& live_region = LiveRegionStatus();
+  return EqualIgnoringASCIICase(live_region, "polite") ||
+         EqualIgnoringASCIICase(live_region, "assertive");
+}
+
+AXObjectImpl* AXObjectImpl::LiveRegionRoot() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_live_region_root_;
+}
+
+const AtomicString& AXObjectImpl::ContainerLiveRegionStatus() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_live_region_root_ ? cached_live_region_root_->LiveRegionStatus()
+                                  : g_null_atom;
+}
+
+const AtomicString& AXObjectImpl::ContainerLiveRegionRelevant() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_live_region_root_
+             ? cached_live_region_root_->LiveRegionRelevant()
+             : g_null_atom;
+}
+
+bool AXObjectImpl::ContainerLiveRegionAtomic() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_live_region_root_ &&
+         cached_live_region_root_->LiveRegionAtomic();
+}
+
+bool AXObjectImpl::ContainerLiveRegionBusy() const {
+  UpdateCachedAttributeValuesIfNeeded();
+  return cached_live_region_root_ && cached_live_region_root_->LiveRegionBusy();
+}
+
+AXObjectImpl* AXObjectImpl::ElementAccessibilityHitTest(
+    const IntPoint& point) const {
+  // Check if there are any mock elements that need to be handled.
+  for (const auto& child : children_) {
+    if (child->IsMockObject() &&
+        child->GetBoundsInFrameCoordinates().Contains(point))
+      return child->ElementAccessibilityHitTest(point);
+  }
+
+  return const_cast<AXObjectImpl*>(this);
+}
+
+const AXObjectImpl::AXObjectVector& AXObjectImpl::Children() {
+  UpdateChildrenIfNecessary();
+
+  return children_;
+}
+
+AXObjectImpl* AXObjectImpl::ParentObject() const {
+  if (IsDetached())
+    return 0;
+
+  if (parent_)
+    return parent_;
+
+  if (AxObjectCache().IsAriaOwned(this))
+    return AxObjectCache().GetAriaOwnedParent(this);
+
+  return ComputeParent();
+}
+
+AXObjectImpl* AXObjectImpl::ParentObjectIfExists() const {
+  if (IsDetached())
+    return 0;
+
+  if (parent_)
+    return parent_;
+
+  return ComputeParentIfExists();
+}
+
+AXObjectImpl* AXObjectImpl::ParentObjectUnignored() const {
+  AXObjectImpl* parent;
+  for (parent = ParentObject(); parent && parent->AccessibilityIsIgnored();
+       parent = parent->ParentObject()) {
+  }
+
+  return parent;
+}
+
+void AXObjectImpl::UpdateChildrenIfNecessary() {
+  if (!HasChildren())
+    AddChildren();
+}
+
+void AXObjectImpl::ClearChildren() {
+  // Detach all weak pointers from objects to their parents.
+  for (const auto& child : children_)
+    child->DetachFromParent();
+
+  children_.clear();
+  have_children_ = false;
+}
+
+Document* AXObjectImpl::GetDocument() const {
+  FrameView* frame_view = DocumentFrameView();
+  if (!frame_view)
+    return 0;
+
+  return frame_view->GetFrame().GetDocument();
+}
+
+FrameView* AXObjectImpl::DocumentFrameView() const {
+  const AXObjectImpl* object = this;
+  while (object && !object->IsAXLayoutObject())
+    object = object->ParentObject();
+
+  if (!object)
+    return 0;
+
+  return object->DocumentFrameView();
+}
+
+String AXObjectImpl::Language() const {
+  const AtomicString& lang = GetAttribute(langAttr);
+  if (!lang.IsEmpty())
+    return lang;
+
+  AXObjectImpl* parent = ParentObject();
+
+  // As a last resort, fall back to the content language specified in the meta
+  // tag.
+  if (!parent) {
+    Document* doc = GetDocument();
+    if (doc)
+      return doc->ContentLanguage();
+    return g_null_atom;
+  }
+
+  return parent->Language();
+}
+
+bool AXObjectImpl::HasAttribute(const QualifiedName& attribute) const {
+  Node* element_node = GetNode();
+  if (!element_node)
+    return false;
+
+  if (!element_node->IsElementNode())
+    return false;
+
+  Element* element = ToElement(element_node);
+  return element->FastHasAttribute(attribute);
+}
+
+const AtomicString& AXObjectImpl::GetAttribute(
+    const QualifiedName& attribute) const {
+  Node* element_node = GetNode();
+  if (!element_node)
+    return g_null_atom;
+
+  if (!element_node->IsElementNode())
+    return g_null_atom;
+
+  Element* element = ToElement(element_node);
+  return element->FastGetAttribute(attribute);
+}
+
+//
+// Scrollable containers.
+//
+
+bool AXObjectImpl::IsScrollableContainer() const {
+  return !!GetScrollableAreaIfScrollable();
+}
+
+IntPoint AXObjectImpl::GetScrollOffset() const {
+  ScrollableArea* area = GetScrollableAreaIfScrollable();
+  if (!area)
+    return IntPoint();
+
+  return IntPoint(area->ScrollOffsetInt().Width(),
+                  area->ScrollOffsetInt().Height());
+}
+
+IntPoint AXObjectImpl::MinimumScrollOffset() const {
+  ScrollableArea* area = GetScrollableAreaIfScrollable();
+  if (!area)
+    return IntPoint();
+
+  return IntPoint(area->MinimumScrollOffsetInt().Width(),
+                  area->MinimumScrollOffsetInt().Height());
+}
+
+IntPoint AXObjectImpl::MaximumScrollOffset() const {
+  ScrollableArea* area = GetScrollableAreaIfScrollable();
+  if (!area)
+    return IntPoint();
+
+  return IntPoint(area->MaximumScrollOffsetInt().Width(),
+                  area->MaximumScrollOffsetInt().Height());
+}
+
+void AXObjectImpl::SetScrollOffset(const IntPoint& offset) const {
+  ScrollableArea* area = GetScrollableAreaIfScrollable();
+  if (!area)
+    return;
+
+  // TODO(bokan): This should potentially be a UserScroll.
+  area->SetScrollOffset(ScrollOffset(offset.X(), offset.Y()),
+                        kProgrammaticScroll);
+}
+
+void AXObjectImpl::GetRelativeBounds(
+    AXObjectImpl** out_container,
+    FloatRect& out_bounds_in_container,
+    SkMatrix44& out_container_transform) const {
+  *out_container = nullptr;
+  out_bounds_in_container = FloatRect();
+  out_container_transform.setIdentity();
+
+  // First check if it has explicit bounds, for example if this element is tied
+  // to a canvas path. When explicit coordinates are provided, the ID of the
+  // explicit container element that the coordinates are relative to must be
+  // provided too.
+  if (!explicit_element_rect_.IsEmpty()) {
+    *out_container = AxObjectCache().ObjectFromAXID(explicit_container_id_);
+    if (*out_container) {
+      out_bounds_in_container = FloatRect(explicit_element_rect_);
+      return;
+    }
+  }
+
+  LayoutObject* layout_object = LayoutObjectForRelativeBounds();
+  if (!layout_object)
+    return;
+
+  if (IsWebArea()) {
+    if (layout_object->GetFrame()->View()) {
+      out_bounds_in_container.SetSize(
+          FloatSize(layout_object->GetFrame()->View()->ContentsSize()));
+    }
+    return;
+  }
+
+  // First compute the container. The container must be an ancestor in the
+  // accessibility tree, and its LayoutObject must be an ancestor in the layout
+  // tree. Get the first such ancestor that's either scrollable or has a paint
+  // layer.
+  AXObjectImpl* container = ParentObjectUnignored();
+  LayoutObject* container_layout_object = nullptr;
+  while (container) {
+    container_layout_object = container->GetLayoutObject();
+    if (container_layout_object &&
+        container_layout_object->IsBoxModelObject() &&
+        layout_object->IsDescendantOf(container_layout_object)) {
+      if (container->IsScrollableContainer() ||
+          container_layout_object->HasLayer())
+        break;
+    }
+
+    container = container->ParentObjectUnignored();
+  }
+
+  if (!container)
+    return;
+  *out_container = container;
+  out_bounds_in_container =
+      layout_object->LocalBoundingBoxRectForAccessibility();
+
+  // If the container has a scroll offset, subtract that out because we want our
+  // bounds to be relative to the *unscrolled* position of the container object.
+  ScrollableArea* scrollable_area = container->GetScrollableAreaIfScrollable();
+  if (scrollable_area && !container->IsWebArea()) {
+    ScrollOffset scroll_offset = scrollable_area->GetScrollOffset();
+    out_bounds_in_container.Move(scroll_offset);
+  }
+
+  // Compute the transform between the container's coordinate space and this
+  // object.  If the transform is just a simple translation, apply that to the
+  // bounding box, but if it's a non-trivial transformation like a rotation,
+  // scaling, etc. then return the full matrix instead.
+  TransformationMatrix transform = layout_object->LocalToAncestorTransform(
+      ToLayoutBoxModelObject(container_layout_object));
+  if (transform.IsIdentityOr2DTranslation()) {
+    out_bounds_in_container.Move(transform.To2DTranslation());
+  } else {
+    out_container_transform = TransformationMatrix::ToSkMatrix44(transform);
+  }
+}
+
+LayoutRect AXObjectImpl::GetBoundsInFrameCoordinates() const {
+  AXObjectImpl* container = nullptr;
+  FloatRect bounds;
+  SkMatrix44 transform;
+  GetRelativeBounds(&container, bounds, transform);
+  FloatRect computed_bounds(0, 0, bounds.Width(), bounds.Height());
+  while (container && container != this) {
+    computed_bounds.Move(bounds.X(), bounds.Y());
+    if (!container->IsWebArea()) {
+      computed_bounds.Move(-container->GetScrollOffset().X(),
+                           -container->GetScrollOffset().Y());
+    }
+    if (!transform.isIdentity()) {
+      TransformationMatrix transformation_matrix(transform);
+      transformation_matrix.MapRect(computed_bounds);
+    }
+    container->GetRelativeBounds(&container, bounds, transform);
+  }
+  return LayoutRect(computed_bounds);
+}
+
+//
+// Modify or take an action on an object.
+//
+
+bool AXObjectImpl::Press() {
+  Document* document = GetDocument();
+  if (!document)
+    return false;
+
+  UserGestureIndicator gesture_indicator(DocumentUserGestureToken::Create(
+      document, UserGestureToken::kNewGesture));
+  Element* action_elem = ActionElement();
+  if (action_elem) {
+    action_elem->AccessKeyAction(true);
+    return true;
+  }
+
+  if (CanSetFocusAttribute()) {
+    SetFocused(true);
+    return true;
+  }
+
+  return false;
+}
+
+void AXObjectImpl::ScrollToMakeVisible() const {
+  IntRect object_rect = PixelSnappedIntRect(GetBoundsInFrameCoordinates());
+  object_rect.SetLocation(IntPoint());
+  ScrollToMakeVisibleWithSubFocus(object_rect);
+}
+
+// This is a 1-dimensional scroll offset helper function that's applied
+// separately in the horizontal and vertical directions, because the
+// logic is the same. The goal is to compute the best scroll offset
+// in order to make an object visible within a viewport.
+//
+// If the object is already fully visible, returns the same scroll
+// offset.
+//
+// In case the whole object cannot fit, you can specify a
+// subfocus - a smaller region within the object that should
+// be prioritized. If the whole object can fit, the subfocus is
+// ignored.
+//
+// If possible, the object and subfocus are centered within the
+// viewport.
+//
+// Example 1: the object is already visible, so nothing happens.
+//   +----------Viewport---------+
+//                 +---Object---+
+//                 +--SubFocus--+
+//
+// Example 2: the object is not fully visible, so it's centered
+// within the viewport.
+//   Before:
+//   +----------Viewport---------+
+//                         +---Object---+
+//                         +--SubFocus--+
+//
+//   After:
+//                 +----------Viewport---------+
+//                         +---Object---+
+//                         +--SubFocus--+
+//
+// Example 3: the object is larger than the viewport, so the
+// viewport moves to show as much of the object as possible,
+// while also trying to center the subfocus.
+//   Before:
+//   +----------Viewport---------+
+//     +---------------Object--------------+
+//                         +-SubFocus-+
+//
+//   After:
+//             +----------Viewport---------+
+//     +---------------Object--------------+
+//                         +-SubFocus-+
+//
+// When constraints cannot be fully satisfied, the min
+// (left/top) position takes precedence over the max (right/bottom).
+//
+// Note that the return value represents the ideal new scroll offset.
+// This may be out of range - the calling function should clip this
+// to the available range.
+static int ComputeBestScrollOffset(int current_scroll_offset,
+                                   int subfocus_min,
+                                   int subfocus_max,
+                                   int object_min,
+                                   int object_max,
+                                   int viewport_min,
+                                   int viewport_max) {
+  int viewport_size = viewport_max - viewport_min;
+
+  // If the object size is larger than the viewport size, consider
+  // only a portion that's as large as the viewport, centering on
+  // the subfocus as much as possible.
+  if (object_max - object_min > viewport_size) {
+    // Since it's impossible to fit the whole object in the
+    // viewport, exit now if the subfocus is already within the viewport.
+    if (subfocus_min - current_scroll_offset >= viewport_min &&
+        subfocus_max - current_scroll_offset <= viewport_max)
+      return current_scroll_offset;
+
+    // Subfocus must be within focus.
+    subfocus_min = std::max(subfocus_min, object_min);
+    subfocus_max = std::min(subfocus_max, object_max);
+
+    // Subfocus must be no larger than the viewport size; favor top/left.
+    if (subfocus_max - subfocus_min > viewport_size)
+      subfocus_max = subfocus_min + viewport_size;
+
+    // Compute the size of an object centered on the subfocus, the size of the
+    // viewport.
+    int centered_object_min = (subfocus_min + subfocus_max - viewport_size) / 2;
+    int centered_object_max = centered_object_min + viewport_size;
+
+    object_min = std::max(object_min, centered_object_min);
+    object_max = std::min(object_max, centered_object_max);
+  }
+
+  // Exit now if the focus is already within the viewport.
+  if (object_min - current_scroll_offset >= viewport_min &&
+      object_max - current_scroll_offset <= viewport_max)
+    return current_scroll_offset;
+
+  // Center the object in the viewport.
+  return (object_min + object_max - viewport_min - viewport_max) / 2;
+}
+
+void AXObjectImpl::ScrollToMakeVisibleWithSubFocus(
+    const IntRect& subfocus) const {
+  // Search up the parent chain until we find the first one that's scrollable.
+  const AXObjectImpl* scroll_parent = ParentObject() ? ParentObject() : this;
+  ScrollableArea* scrollable_area = 0;
+  while (scroll_parent) {
+    scrollable_area = scroll_parent->GetScrollableAreaIfScrollable();
+    if (scrollable_area)
+      break;
+    scroll_parent = scroll_parent->ParentObject();
+  }
+  if (!scroll_parent || !scrollable_area)
+    return;
+
+  IntRect object_rect = PixelSnappedIntRect(GetBoundsInFrameCoordinates());
+  IntSize scroll_offset = scrollable_area->ScrollOffsetInt();
+  IntRect scroll_visible_rect = scrollable_area->VisibleContentRect();
+
+  // Convert the object rect into local coordinates.
+  if (!scroll_parent->IsWebArea()) {
+    object_rect.MoveBy(IntPoint(scroll_offset));
+    object_rect.MoveBy(
+        -PixelSnappedIntRect(scroll_parent->GetBoundsInFrameCoordinates())
+             .Location());
+  }
+
+  int desired_x = ComputeBestScrollOffset(
+      scroll_offset.Width(), object_rect.X() + subfocus.X(),
+      object_rect.X() + subfocus.MaxX(), object_rect.X(), object_rect.MaxX(), 0,
+      scroll_visible_rect.Width());
+  int desired_y = ComputeBestScrollOffset(
+      scroll_offset.Height(), object_rect.Y() + subfocus.Y(),
+      object_rect.Y() + subfocus.MaxY(), object_rect.Y(), object_rect.MaxY(), 0,
+      scroll_visible_rect.Height());
+
+  scroll_parent->SetScrollOffset(IntPoint(desired_x, desired_y));
+
+  // Convert the subfocus into the coordinates of the scroll parent.
+  IntRect new_subfocus = subfocus;
+  IntRect new_element_rect = PixelSnappedIntRect(GetBoundsInFrameCoordinates());
+  IntRect scroll_parent_rect =
+      PixelSnappedIntRect(scroll_parent->GetBoundsInFrameCoordinates());
+  new_subfocus.Move(new_element_rect.X(), new_element_rect.Y());
+  new_subfocus.Move(-scroll_parent_rect.X(), -scroll_parent_rect.Y());
+
+  if (scroll_parent->ParentObject()) {
+    // Recursively make sure the scroll parent itself is visible.
+    scroll_parent->ScrollToMakeVisibleWithSubFocus(new_subfocus);
+  } else {
+    // To minimize the number of notifications, only fire one on the topmost
+    // object that has been scrolled.
+    AxObjectCache().PostNotification(const_cast<AXObjectImpl*>(this),
+                                     AXObjectCacheImpl::kAXLocationChanged);
+  }
+}
+
+void AXObjectImpl::ScrollToGlobalPoint(const IntPoint& global_point) const {
+  // Search up the parent chain and create a vector of all scrollable parent
+  // objects and ending with this object itself.
+  HeapVector<Member<const AXObjectImpl>> objects;
+  AXObjectImpl* parent_object;
+  for (parent_object = this->ParentObject(); parent_object;
+       parent_object = parent_object->ParentObject()) {
+    if (parent_object->GetScrollableAreaIfScrollable())
+      objects.push_front(parent_object);
+  }
+  objects.push_back(this);
+
+  // Start with the outermost scrollable (the main window) and try to scroll the
+  // next innermost object to the given point.
+  int offset_x = 0, offset_y = 0;
+  IntPoint point = global_point;
+  size_t levels = objects.size() - 1;
+  for (size_t i = 0; i < levels; i++) {
+    const AXObjectImpl* outer = objects[i];
+    const AXObjectImpl* inner = objects[i + 1];
+    ScrollableArea* scrollable_area = outer->GetScrollableAreaIfScrollable();
+
+    IntRect inner_rect =
+        inner->IsWebArea()
+            ? PixelSnappedIntRect(
+                  inner->ParentObject()->GetBoundsInFrameCoordinates())
+            : PixelSnappedIntRect(inner->GetBoundsInFrameCoordinates());
+    IntRect object_rect = inner_rect;
+    IntSize scroll_offset = scrollable_area->ScrollOffsetInt();
+
+    // Convert the object rect into local coordinates.
+    object_rect.Move(offset_x, offset_y);
+    if (!outer->IsWebArea())
+      object_rect.Move(scroll_offset.Width(), scroll_offset.Height());
+
+    int desired_x = ComputeBestScrollOffset(
+        0, object_rect.X(), object_rect.MaxX(), object_rect.X(),
+        object_rect.MaxX(), point.X(), point.X());
+    int desired_y = ComputeBestScrollOffset(
+        0, object_rect.Y(), object_rect.MaxY(), object_rect.Y(),
+        object_rect.MaxY(), point.Y(), point.Y());
+    outer->SetScrollOffset(IntPoint(desired_x, desired_y));
+
+    if (outer->IsWebArea() && !inner->IsWebArea()) {
+      // If outer object we just scrolled is a web area (frame) but the inner
+      // object is not, keep track of the coordinate transformation to apply to
+      // future nested calculations.
+      scroll_offset = scrollable_area->ScrollOffsetInt();
+      offset_x -= (scroll_offset.Width() + point.X());
+      offset_y -= (scroll_offset.Height() + point.Y());
+      point.Move(scroll_offset.Width() - inner_rect.Width(),
+                 scroll_offset.Height() - inner_rect.Y());
+    } else if (inner->IsWebArea()) {
+      // Otherwise, if the inner object is a web area, reset the coordinate
+      // transformation.
+      offset_x = 0;
+      offset_y = 0;
+    }
+  }
+
+  // To minimize the number of notifications, only fire one on the topmost
+  // object that has been scrolled.
+  DCHECK(objects[0]);
+  // TODO(nektar): Switch to postNotification(objects[0] and remove |getNode|.
+  AxObjectCache().PostNotification(objects[0]->GetNode(),
+                                   AXObjectCacheImpl::kAXLocationChanged);
+}
+
+void AXObjectImpl::SetSequentialFocusNavigationStartingPoint() {
+  // Call it on the nearest ancestor that overrides this with a specific
+  // implementation.
+  if (ParentObject())
+    ParentObject()->SetSequentialFocusNavigationStartingPoint();
+}
+
+void AXObjectImpl::NotifyIfIgnoredValueChanged() {
+  bool is_ignored = AccessibilityIsIgnored();
+  if (LastKnownIsIgnoredValue() != is_ignored) {
+    AxObjectCache().ChildrenChanged(ParentObject());
+    SetLastKnownIsIgnoredValue(is_ignored);
+  }
+}
+
+void AXObjectImpl::SelectionChanged() {
+  if (AXObjectImpl* parent = ParentObjectIfExists())
+    parent->SelectionChanged();
+}
+
+int AXObjectImpl::LineForPosition(const VisiblePosition& position) const {
+  if (position.IsNull() || !GetNode())
+    return -1;
+
+  // If the position is not in the same editable region as this AX object,
+  // return -1.
+  Node* container_node = position.DeepEquivalent().ComputeContainerNode();
+  if (!container_node->IsShadowIncludingInclusiveAncestorOf(GetNode()) &&
+      !GetNode()->IsShadowIncludingInclusiveAncestorOf(container_node))
+    return -1;
+
+  int line_count = -1;
+  VisiblePosition current_position = position;
+  VisiblePosition previous_position;
+
+  // Move up until we get to the top.
+  // FIXME: This only takes us to the top of the rootEditableElement, not the
+  // top of the top document.
+  do {
+    previous_position = current_position;
+    current_position = PreviousLinePosition(current_position, LayoutUnit(),
+                                            kHasEditableAXRole);
+    ++line_count;
+  } while (current_position.IsNotNull() &&
+           !InSameLine(current_position, previous_position));
+
+  return line_count;
+}
+
+bool AXObjectImpl::IsARIAControl(AccessibilityRole aria_role) {
+  return IsARIAInput(aria_role) || aria_role == kButtonRole ||
+         aria_role == kComboBoxRole || aria_role == kSliderRole;
+}
+
+bool AXObjectImpl::IsARIAInput(AccessibilityRole aria_role) {
+  return aria_role == kRadioButtonRole || aria_role == kCheckBoxRole ||
+         aria_role == kTextFieldRole || aria_role == kSwitchRole ||
+         aria_role == kSearchBoxRole;
+}
+
+AccessibilityRole AXObjectImpl::AriaRoleToWebCoreRole(const String& value) {
+  DCHECK(!value.IsEmpty());
+
+  static const ARIARoleMap* role_map = CreateARIARoleMap();
+
+  Vector<String> role_vector;
+  value.Split(' ', role_vector);
+  AccessibilityRole role = kUnknownRole;
+  for (const auto& child : role_vector) {
+    role = role_map->at(child);
+    if (role)
+      return role;
+  }
+
+  return role;
+}
+
+bool AXObjectImpl::IsInsideFocusableElementOrARIAWidget(const Node& node) {
+  const Node* cur_node = &node;
+  do {
+    if (cur_node->IsElementNode()) {
+      const Element* element = ToElement(cur_node);
+      if (element->IsFocusable())
+        return true;
+      String role = element->getAttribute("role");
+      if (!role.IsEmpty() && AXObjectImpl::IncludesARIAWidgetRole(role))
+        return true;
+      if (HasInteractiveARIAAttribute(*element))
+        return true;
+    }
+    cur_node = cur_node->parentNode();
+  } while (cur_node && !isHTMLBodyElement(node));
+  return false;
+}
+
+bool AXObjectImpl::HasInteractiveARIAAttribute(const Element& element) {
+  for (size_t i = 0; i < WTF_ARRAY_LENGTH(g_aria_interactive_widget_attributes);
+       ++i) {
+    const char* attribute = g_aria_interactive_widget_attributes[i];
+    if (element.hasAttribute(attribute)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool AXObjectImpl::IncludesARIAWidgetRole(const String& role) {
+  static const HashSet<String, CaseFoldingHash>* role_set =
+      CreateARIARoleWidgetSet();
+
+  Vector<String> role_vector;
+  role.Split(' ', role_vector);
+  for (const auto& child : role_vector) {
+    if (role_set->Contains(child))
+      return true;
+  }
+  return false;
+}
+
+bool AXObjectImpl::NameFromContents() const {
+  // ARIA 1.1, section 5.2.7.5.
+  switch (RoleValue()) {
+    case kAnchorRole:
+    case kButtonRole:
+    case kCellRole:
+    case kCheckBoxRole:
+    case kColumnHeaderRole:
+    case kDirectoryRole:
+    case kDisclosureTriangleRole:
+    case kHeadingRole:
+    case kLineBreakRole:
+    case kLinkRole:
+    case kListBoxOptionRole:
+    case kListItemRole:
+    case kMenuItemRole:
+    case kMenuItemCheckBoxRole:
+    case kMenuItemRadioRole:
+    case kMenuListOptionRole:
+    case kPopUpButtonRole:
+    case kRadioButtonRole:
+    case kRowHeaderRole:
+    case kStaticTextRole:
+    case kStatusRole:
+    case kSwitchRole:
+    case kTabRole:
+    case kToggleButtonRole:
+    case kTreeItemRole:
+    case kUserInterfaceTooltipRole:
+      return true;
+    case kRowRole: {
+      // Spec says we should always expose the name on rows,
+      // but for performance reasons we only do it
+      // if the row might receive focus
+      if (AncestorExposesActiveDescendant()) {
+        return true;
+      }
+      const Node* node = this->GetNode();
+      return node && node->IsElementNode() && ToElement(node)->IsFocusable();
+    }
+    default:
+      return false;
+  }
+}
+
+AccessibilityRole AXObjectImpl::ButtonRoleType() const {
+  // If aria-pressed is present, then it should be exposed as a toggle button.
+  // http://www.w3.org/TR/wai-aria/states_and_properties#aria-pressed
+  if (AriaPressedIsPresent())
+    return kToggleButtonRole;
+  if (AriaHasPopup())
+    return kPopUpButtonRole;
+  // We don't contemplate RadioButtonRole, as it depends on the input
+  // type.
+
+  return kButtonRole;
+}
+
+const AtomicString& AXObjectImpl::RoleName(AccessibilityRole role) {
+  static const Vector<AtomicString>* role_name_vector = CreateRoleNameVector();
+
+  return role_name_vector->at(role);
+}
+
+const AtomicString& AXObjectImpl::InternalRoleName(AccessibilityRole role) {
+  static const Vector<AtomicString>* internal_role_name_vector =
+      CreateInternalRoleNameVector();
+
+  return internal_role_name_vector->at(role);
+}
+
+DEFINE_TRACE(AXObjectImpl) {
+  visitor->Trace(children_);
+  visitor->Trace(parent_);
+  visitor->Trace(cached_live_region_root_);
+  visitor->Trace(ax_object_cache_);
+}
+
+}  // namespace blink