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This asks for the layout opporunties up front, then iterates through them
attempting to construct a line for each one, until something fits.

There are two checks:
1) For the inline-size of a linebox, directly after the line breaker has run.
2) For the block-size, after we've determined the line-height.

Bug: 	635619
Change-Id: Icb88791be2c4d267b1361c4a7ed47dec71b9a87d
Reviewed-on: https://chromium-review.googlesource.com/742041
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513318}