Implement the inert attribute

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

Index: third_party/WebKit/Source/modules/accessibility/AXObject.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXObject.cpp b/third_party/WebKit/Source/modules/accessibility/AXObject.cpp
index 2e9b20e6a8035cd0d300595e0428bb40c482abc3..819ea4f1a92815f54bb93599698a21e4b7587c8e 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObject.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXObject.cpp
@@ -536,10 +536,14 @@ bool AXObject::computeIsInertOrAriaHidden(
             ignoredReasons->push_back(
                 IgnoredReason(AXActiveModalDialog, dialogObject));
           else
-            ignoredReasons->push_back(IgnoredReason(AXInert));
+            ignoredReasons->push_back(IgnoredReason(AXInertElement));
         } else {
-          // TODO(aboxhall): handle inert attribute if it eventuates
-          ignoredReasons->push_back(IgnoredReason(AXInert));
+          const AXObject* inertRoot = this->inertRoot();
+          if (inertRoot == this) {
+            ignoredReasons->push_back(IgnoredReason(AXInertElement));
+          } else {
+            ignoredReasons->push_back(IgnoredReason(AXInertSubtree, inertRoot));
+          }
         }
       }
       return true;
@@ -556,10 +560,12 @@ bool AXObject::computeIsInertOrAriaHidden(
   const AXObject* hiddenRoot = ariaHiddenRoot();
   if (hiddenRoot) {
     if (ignoredReasons) {
-      if (hiddenRoot == this)
-        ignoredReasons->push_back(IgnoredReason(AXAriaHidden));
-      else
-        ignoredReasons->push_back(IgnoredReason(AXAriaHiddenRoot, hiddenRoot));
+      if (hiddenRoot == this) {
+        ignoredReasons->push_back(IgnoredReason(AXAriaHiddenElement));
+      } else {
+        ignoredReasons->push_back(
+            IgnoredReason(AXAriaHiddenSubtree, hiddenRoot));
+      }
     }
     return true;
   }
@@ -592,6 +598,24 @@ const AXObject* AXObject::ariaHiddenRoot() const {
   return 0;
 }
 
+const AXObject* AXObject::inertRoot() const {
+  const AXObject* object = this;
+  if (!RuntimeEnabledFeatures::inertAttributeEnabled())
+    return nullptr;
+
+  while (object && !object->isAXNodeObject())
+    object = object->parentObject();
+  for (Node* node = object->getNode(); node;
+       node = FlatTreeTraversal::parentElement(*node)) {
+    if (!node->isElementNode())
+      continue;
+    if (toElement(node)->hasAttribute(inertAttr))
+      return axObjectCache().getOrCreate(node);
+  }
+
+  return nullptr;
+}
+
 bool AXObject::isDescendantOfDisabledNode() const {
   updateCachedAttributeValuesIfNeeded();
   return m_cachedIsDescendantOfDisabledNode;