Refactor CanvasStateTest to pull out functions which can
either be called directly or from a shared library. Add a
command line flag to pass in the path to a library to open
to call those functions from.
Separate different CanvasTest tests into separate DEF_TEST
tests. This allows them to be run in parallel.
Move the ifdefs outside of function declarations to skip
running CanvasTest tests which do nothing.
Add the canvas_state_lib target. It is a shared library that
exports some functions to be called by another version of
Skia.
BUG=b/15693384
R=djsollen@google.com, reed@google.com
Author: scroggo@google.com
Review URL: https://codereview.chromium.org/400043003
