OffscreenCanvas 2d context conformance tests - part 4 (#4277)

This pull request is a follow up for our previous one:
https://github.com/w3c/web-platform-tests/pull/4274#event-880050484

We add 328 tests here. After this, there will be one more.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/4277

Received on Friday, 2 December 2016 14:39:31 UTC