Remove legacy markup box behavior when line-clamping.

Remove legacy forced display/hit-testing of trailing anchor text when line-clamping.

Summarizing the legacy behavior: clamped text would be
ellipsified, but there was a special case where trailing anchor
text, if any, would always be painted and hit-tested. This was
intended to allow behavior as "Some text... [More]" where
"[More]" was an anchor link and certain to be shown.

There are alternate ways to achieve this behavior, so we simplify
the code via removal.

BUG=474343
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=193299

[wkorman, 2015-04-07 01:36:25]

wkorman@chromium.org changed reviewers:
+ chrishtr@chromium.org

[chrishtr, 2015-04-07 18:03:01]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2015-04-07 18:03:02]

lgtm

[commit-bot: I haz the power, 2015-04-07 18:03:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1065783002/40001

[commit-bot: I haz the power, 2015-04-07 20:34:01]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=193299