animation timing. This allows us to "freeze" time in order to do things like
draw multiple times to test clipping.
git-svn-id: http://skia.googlecode.com/svn/trunk@444 2bbb7eff-a529-9590-31e7-b0007b416f81
rename setXfermode(Mode) to setXfermodeMode(Mode) for sanity
fix memory leak in setXfermode(Mode)
git-svn-id: http://skia.googlecode.com/svn/trunk@239 2bbb7eff-a529-9590-31e7-b0007b416f81