Selection follows focus/activedescendant in single selection containers

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
index 37699ded8eb6daca5aa78529441b7caa1843913c..e30e4a4005faf14054d76d89cb18fce95c517156 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXObjectImpl.cpp
@@ -774,7 +774,7 @@ bool AXObjectImpl::ComputeAncestorExposesActiveDescendant() const {
     return false;
 
   if (parent->SupportsActiveDescendant() &&
-      !parent->GetAttribute(aria_activedescendantAttr).IsEmpty()) {
+      parent->HasAttribute(aria_activedescendantAttr)) {
     return true;
   }
 
@@ -1255,6 +1255,35 @@ AXObjectImpl* AXObjectImpl::ParentObjectUnignored() const {
   return parent;
 }
 
+// Container widgets are those that a user tabs into and arrows around
+// sub-widgets
+bool AXObjectImpl::IsContainerWidget() const {
+  switch (RoleValue()) {
+    case kComboBoxRole:
+    case kGridRole:
+    case kListBoxRole:
+    case kMenuBarRole:
+    case kMenuRole:
+    case kRadioGroupRole:
+    case kSpinButtonRole:
+    case kTabListRole:
+    case kToolbarRole:
+    case kTreeGridRole:
+    case kTreeRole:
+      return true;
+    default:
+      return false;
+  }
+}
+
+AXObjectImpl* AXObjectImpl::ContainerWidget() const {
+  AXObjectImpl* ancestor = ParentObjectUnignored();
+  while (ancestor && !ancestor->IsContainerWidget())
+    ancestor = ancestor->ParentObjectUnignored();
+
+  return ancestor;
+}
+
 void AXObjectImpl::UpdateChildrenIfNecessary() {
   if (!HasChildren())
     AddChildren();