Paint invalidation tests for slimming paint v2

Add a new type of paint invalidation test for slimming paint v2.

- They are reftests, to check the correctness of painted result;
- Tracks paint invalidation objects and checks them against expected

This CL converts two paint/invalidation tests into the new style.

Will convert some fast/repaint and compositing/repaint tests into this
style for spv2 after this CL. The original tests are not suitable for
spv2 because
- it's hard to determine if a test is actually failing or needs
  rebaseline for spv2;
- they don't cover correctness of paint results.


Review URL:

git-svn-id: svn:// bbb929c8-8fbe-4397-9dbb-9b2b20218538
14 files changed
tree: ee6ad40b4df58e43d91201671e156dc80b34c08f
  1. third_party/