Implement the scale factor variant of ShareableBitmap::paint(). One such usage of this variant is in changeset <http://trac.webkit.org/changeset/91085>. In particular, the change to Source/WebKit2/UIProcess/FindIndicator.cpp. For completeness, the scale factor variant of ShareableBitmap::paint() was added to the CG port in <http://trac.webkit.org/changeset/90198>.
Committed sub method in <http://trac.webkit.org/changeset/91163>.