Should ClientValidationRuleFactory be exposed to users?

[dougbu]

In the old world, HtmlHelper had an internal property named ClientValidationRuleFactory. We probably don't want to maintain it as internal but also likely want to make something available to subclasses choosing to override GetValidationAttributes(), assuming we decide to make that method virtual.
his property was frequently used in unit tests to mock validation errors or other validation results during tests. Since our validation abstractions are changing significantly, we should keep this use case in mind when completing the client-side validation implementation in the new world.

[dougbu]

The (public) HtmlHelper.GetClientValidationRules() method and fact HtmlHelper.GetValidationAttributes() is protected virtual provide everything HtmlHelper subclasses need in this area. Reopen if we get pushback.