LibGUI: Add glyph substitution to TextEditor

This patch adds the member variable m_substitution_code_point to
GUI::TextEditor. If non-zero, all gylphs to be drawn will be substituted
with the specified code point. This is mainly needed to support a
PasswordBox.

While the primary use-case is for single-line editors, multi-line
editors are also supported.

To prevent repeated String construction, a m_substitution_string_data
members has been added, which is an OwnPtr<Vector<u32>>. This is used as
a UTF-32 string builder. The substitution_code_point_view method uses
that Vector to provide a Utf32View of the specified length.

0 files changed, 0 insertions, 0 deletions