Remove default argument on ComputedStyle::setHasViewportUnits().

Currently ComputedStyle::setHasViewportUnits() takes a boolean argument,
which defaults to true. We would like to generate this field in a future
patch, but we can't generate this type of setter yet. This patch removes
the default argument on setHasViewportUnits() so that this setter can be
generated without changing the generator. All the callers are updated to
explicitly specify an argument as well.

This is prework for generating setHasViewportUnits.

BUG=628043

Review-Url: https://codereview.chromium.org/2767853002
Cr-Commit-Position: refs/heads/master@{#462270}
2 files changed