Also make SkGPipeController ref the recording canvas to ensure that
objects used by SkGPipeCanvas (e.g. SharedHeap and fTypefaceSet, which
hold references to objects to which pointers are written to the stream)
survive to be played back even if SkGPipeWriter.endRecording() is called.
BUG=
TEST=TypefaceGM
Review URL: https://codereview.appspot.com/6447055
git-svn-id: http://skia.googlecode.com/svn/trunk@4817 2bbb7eff-a529-9590-31e7-b0007b416f81
scroggo@google.com