add 'r' (rotate) 's' (scale) options to SampleApp to test those matrix ops on
all slides

add beforeChild/afterChild methods for parents to wack the canvas before/after
it draws. These are called after the std child-view translate and clip, unlike
beforeChildren/afterChildren



git-svn-id: http://skia.googlecode.com/svn/trunk@324 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed