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 3493cfab9c89cfb0bca1df0b50bb7236c29b86ab..fe1b38bd477039a30e8d3a7276cd8c0553dc5258 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObject.h
+++ b/third_party/WebKit/Source/modules/accessibility/AXObject.h
@@ -359,6 +359,7 @@ enum AXIgnoredReason {
     AXEmptyAlt,
     AXEmptyText,
     AXInert,
+    AXInertRoot,

[dmazzoni, 2016/06/29 17:00:56]

I wonder if AXInInertSubtree would be more clear (and similarly for
AXAriaHiddenRoot)?

After not looking at this code for a while, I remembered the difference between
AXAriaHidden and AXAriaHiddenRoot but I couldn't recall which one *is* the root
and which one is hidden *because* of a root.

     AXInheritsPresentation,
     AXLabelContainer,
     AXLabelFor,
@@ -662,6 +663,7 @@ public:
     AXObjectInclusion accessibilityPlatformIncludesObject() const;
     virtual AXObjectInclusion defaultObjectInclusion(IgnoredReasons* = nullptr) const;
     bool isInertOrAriaHidden() const;
+    const AXObject* inertRoot() const;
     const AXObject* ariaHiddenRoot() const;
     bool computeIsInertOrAriaHidden(IgnoredReasons* = nullptr) const;
     bool isDescendantOfLeafNode() const;