test (and fix) clip_restriction in canvas

BUG=skia:

Change-Id: I86d25d0fd82be35d01471fba59f77b360be5373c
Reviewed-on: https://skia-review.googlesource.com/9995
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Derek Sollenberger <djsollen@google.com>
4 files changed