canvas-index.css comes from
http://w3c-test.org/html/tests/approved/common/canvas-index.css
without any modification.

a-green.css comes from
http://test.csswg.org/source/approved/css-masking/src/support/a-green.css
without any modification.

These tests are copyright by W3C and/or the author listed in the test
file. The tests are dual-licensed under the W3C Test Suite License:
http://www.w3.org/Consortium/Legal/2008/04-testsuite-license
and the BSD 3-clause License:
http://www.w3.org/Consortium/Legal/2008/03-bsd-license
under W3C's test suite licensing policy:
http://www.w3.org/Consortium/Legal/2008/04-testsuite-copyright


