[text-box-trim] trim the last line
This CL implements the logic of changing the last non-empty node's size
of a block with text-box-trim:end/both specified.
Bug: 40254880
Change-Id: I19c70f69a549a2d5b5740e491f9190679e596f7a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5553234
Reviewed-by: Koji Ishii kojii@chromium.org
Commit-Queue: Lingqi Chi lingqi@chromium.org
Cr-Commit-Position: refs/heads/main@{#1303658}