Function layout_2013::text::apply_style_transform_if_necessary

fn apply_style_transform_if_necessary(
    string: &mut String,
    first_character_position: usize,
    text_transform: TextTransform,
    last_whitespace: bool,
    is_first_run: bool,
)

Accounts for text-transform.

FIXME(#4311, pcwalton): Title-case mapping can change length of the string; case mapping should be language-specific; full-width; use graphemes instead of characters.