Implement the inert attribute

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

Index: third_party/WebKit/Source/modules/accessibility/AXObject.h
diff --git a/third_party/WebKit/Source/modules/accessibility/AXObject.h b/third_party/WebKit/Source/modules/accessibility/AXObject.h
index 090f8f1b11988f0313a68ee8fbcc919c77f2b0c4..5458f2a0c5daa05adde08b2adaa17a3d1073503e 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObject.h
+++ b/third_party/WebKit/Source/modules/accessibility/AXObject.h
@@ -395,11 +395,12 @@ enum AXIgnoredReason {
   AXActiveModalDialog,
   AXAncestorDisallowsChild,
   AXAncestorIsLeafNode,
-  AXAriaHidden,
-  AXAriaHiddenRoot,
+  AXAriaHiddenElement,
+  AXAriaHiddenSubtree,
   AXEmptyAlt,
   AXEmptyText,
-  AXInert,
+  AXInertElement,
+  AXInertSubtree,
   AXInheritsPresentation,
   AXLabelContainer,
   AXLabelFor,
@@ -1076,6 +1077,8 @@ class MODULES_EXPORT AXObject : public GarbageCollectedFinalized<AXObject> {
     return nullptr;
   }
 
+  const AXObject* inertRoot() const;
+
   mutable Member<AXObject> m_parent;
 
   // The following cached attribute values (the ones starting with m_cached*)