Use Initial Containing Block size for vertical

This patch fixes the vertical modes assert in ComputeInlineLength.

I used box.view()->viewportSizeForViewportUnits() for ICB size
per kojii's suggestion.

BUG=635619

Review-Url: https://codereview.chromium.org/2681783004
Cr-Commit-Position: refs/heads/master@{#449818}
9 files changed