GitLab

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
  list.

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.

BUG=524134

Review URL: https://codereview.chromium.org/1324763002

git-svn-id: svn://svn.chromium.org/blink/trunk@201565 bbb929c8-8fbe-4397-9dbb-9b2b20218538