OffscreenCanvas 2d context conformance tests - part 3 (#4274)

This pull request is a follow up for our previous one:
https://github.com/w3c/web-platform-tests/pull/4265#issuecomment-263870239

In here, we add 420 tests.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/4274

Received on Thursday, 1 December 2016 17:53:24 UTC