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This is adding the interface changes, the code checking for corectedness,
does type conversion and checks for the edge cases mentioned in spec.

This is also adding WPT.

Bug: 907909
Change-Id: Ieebe5b25202a403e50a09576ac283690c0f0ba55
Reviewed-on: https://chromium-review.googlesource.com/c/1348972
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611871}