Switch to equalIgnoringASCIICase throughout modules/accessibility

BUG=627682

Review-Url: https://codereview.chromium.org/2793913007
Cr-Commit-Position: refs/heads/master@{#461858}
bool AXTableCell::isTableCell() const {
  AXObject* parent = parentObjectUnignored();
  if (!parent || !parent->isTableRow())
    return false;

  return true;
}

bool AXTableCell::isTableCell() const {
  AXObject* parent = parentObjectUnignored();
  if (!parent || !parent->isTableRow())
    return false;

  return true;
}
