Reviewed by Darin.

    Reviewed by Darin.

        <rdar://problem/4077676> Inline hole line adheres to the Japanese characters in inline hole

        This happens because the underline is always 2 pixels thick, and placed 3 pixels above the bottom of the text box.

        Test case added:
        * manual-tests/inline-input-marking.html: Added.
        Check that underlining of the inline input hole does not obscure the glyphs.

        * rendering/InlineTextBox.cpp:
        (WebCore::InlineTextBox::paintMarkedTextUnderline):
        Position underline at bottom of text box.
        Height of underline is reduced to 1 px when font's descent is less than or equal to 2 px.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@15971 268f45cc-cd09-0410-ab3c-d52691b4dbfc