Switch to equalIgnoringASCIICase throughout modules/accessibility

BUG=627682

Review-Url: https://codereview.chromium.org/2793913007
Cr-Commit-Position: refs/heads/master@{#461858}
bool AXObject::isARIAInput(AccessibilityRole ariaRole) {
  return ariaRole == RadioButtonRole || ariaRole == CheckBoxRole ||
         ariaRole == TextFieldRole || ariaRole == SwitchRole ||
         ariaRole == SearchBoxRole;
}

bool AXObject::isARIAInput(AccessibilityRole ariaRole) {
  return ariaRole == RadioButtonRole || ariaRole == CheckBoxRole ||
         ariaRole == TextFieldRole || ariaRole == SwitchRole ||
         ariaRole == SearchBoxRole;
}
