Move glyph choosing to the find and place glyph code.

This duplicates the functionality of the (private)
SkPaint::getDrawCacheProc method into
SkFindAndPlaceGlyph::LookupGlyph. Eventually LookupGlyph
should replace getDrawCacheProc, at which point it should be
removed. The remaining users are gpu and pdf.

Review URL: https://codereview.chromium.org/1458193003
3 files changed