Implement DOMTokenList.prototype.replace().

Firefox and Safari already shipped it.
This CL fixes 256 failing tests in external/wpt/.

Intent: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/0P4_WvNr1xY

Bug: 724906
Change-Id: Ic55ead1509afd3e631ed0251fa312bd5b4a7001f
Reviewed-on: https://chromium-review.googlesource.com/521002
Reviewed-by: Takayoshi Kochi <kochi@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476240}
12 files changed