Remove SVGInlineTextBox::m_paintingResourceMode

The field is only being used for passing transient data down the
call stack, and is not a trait of an SVGInlineTextBox (which is
confusing).

Bite the bullet and plumb this as a parameter instead.

R=fs@opera.com,schenney@chromium.org

Review URL: https://codereview.chromium.org/231493003

git-svn-id: svn://svn.chromium.org/blink/trunk@171314 bbb929c8-8fbe-4397-9dbb-9b2b20218538