Restore pre-r118852 behavior for EllipsisBox::nodeAtPoint()
https://bugs.webkit.org/show_bug.cgi?id=109277

Reviewed by Simon Fraser.

Source/WebCore:

Test: fast/flexbox/line-clamp-link-after-ellipsis.html

Roll out r118852. Enough time has passed that this can't be done
mechanically, so transcribe the old method definition to current
WebCore interfaces.

* rendering/EllipsisBox.cpp:
(WebCore::EllipsisBox::markupBox): EllipsisBox no longer has
m_markupBox, so break the logic for finding the markup box from
paintMarkupBox() into its own function.
(WebCore::EllipsisBox::paintMarkupBox): Call markupBox().
(WebCore::EllipsisBox::nodeAtPoint): Transcribe the pre-r118852 implementation.
* rendering/EllipsisBox.h:
(EllipsisBox): Declare markupBox().

LayoutTests:

Remove test added by r118852 and add a test that verifies the original
expected behavior.

* fast/css/text-overflow-ellipsis-hit-test-expected.txt: Removed.
* fast/css/text-overflow-ellipsis-hit-test.html: Removed.
* fast/flexbox/line-clamp-link-after-ellipsis-expected.txt: Added.
* fast/flexbox/line-clamp-link-after-ellipsis.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142335 268f45cc-cd09-0410-ab3c-d52691b4dbfc