Switch to equalIgnoringASCIICase throughout modules/accessibility

BUG=627682

Review-Url: https://codereview.chromium.org/2793913007
Cr-Commit-Position: refs/heads/master@{#461858}
Node* AXLayoutObject::getNode() const {
  return getLayoutObject() ? getLayoutObject()->node() : nullptr;
}

Node* AXLayoutObject::getNode() const {
  return getLayoutObject() ? getLayoutObject()->node() : nullptr;
}
