Implement the inert attribute

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

Index: third_party/WebKit/Source/modules/accessibility/AXObjectImpl.h
diff --git a/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.h b/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.h
index 836f8ad90008241e40dc20835c3da20b4a92a361..a6b8f33c4ff6460d99a0d5ed1be5694399e10556 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.h
+++ b/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.h
@@ -401,11 +401,12 @@ enum AXIgnoredReason {
   kAXActiveModalDialog,
   kAXAncestorDisallowsChild,
   kAXAncestorIsLeafNode,
-  kAXAriaHidden,
-  kAXAriaHiddenRoot,
+  kAXAriaHiddenElement,
+  kAXAriaHiddenSubtree,
   kAXEmptyAlt,
   kAXEmptyText,
-  kAXInert,
+  kAXInertElement,
+  kAXInertSubtree,
   kAXInheritsPresentation,
   kAXLabelContainer,
   kAXLabelFor,
@@ -718,7 +719,7 @@ class MODULES_EXPORT AXObjectImpl
   virtual bool CanSetSelectedAttribute() const { return false; }
 
   // Whether objects are ignored, i.e. not included in the tree.
-  bool AccessibilityIsIgnored() const;
+  bool AccessibilityIsIgnored();
   typedef HeapVector<IgnoredReason> IgnoredReasons;
   virtual bool ComputeAccessibilityIsIgnored(IgnoredReasons* = nullptr) const {
     return true;
@@ -1109,6 +1110,8 @@ class MODULES_EXPORT AXObjectImpl
     return nullptr;
   }
 
+  const AXObjectImpl* InertRoot() const;
+
   mutable Member<AXObjectImpl> parent_;
 
   // The following cached attribute values (the ones starting with m_cached*)