Remove unused KeyboardEvent* arguments of focus-related functions.

Any implementation of Node::isKeyboardFocusable don't access the
KeyboardEvent* argument, and we don't need to pass it in many functions
in FocusController.

- Do not expose a bool argument of FocusController::advanceFocus

- Also, we remove HTMLInputElement::isTextFormControlKeyboardFocusable,
  which is actually just isFocusable(). BaseMultipleFieldsDateAndTimeInputType::
  isKeyboardFocusable and TextFieldInputType::isKeyboardFocusable are
  unnecessary because they are identical to InputType::isKeyboardFocusable.

BUG=258763

Review URL: https://chromiumcodereview.appspot.com/21335002

git-svn-id: svn://svn.chromium.org/blink/trunk@155290 bbb929c8-8fbe-4397-9dbb-9b2b20218538