Whitespace in particular source code changes rendering; does not in Firefox
https://bugs.webkit.org/show_bug.cgi?id=100943

Patch by Arnaud Renevier <a.renevier@sisa.samsung.com> on 2013-04-09
Reviewed by Darin Adler.

Source/WebCore:

A render inline which requires a line box is considered a possible
trailing object. So, ensureLineBoxInsideIgnoredSpaces will be called
for it, even if it is placed after a text render ending with a single
space.

Tests: fast/text/whitespace/trailing-space-before-empty-span-1.html
       fast/text/whitespace/trailing-space-before-empty-span-2.html

* rendering/RenderBlockLineLayout.cpp:
(TrailingObjects):
(WebCore::TrailingObjects::appendBoxIfNeeded):
(WebCore::RenderBlock::LineBreaker::nextSegmentBreak):

LayoutTests:

* fast/text/whitespace/trailing-space-before-empty-span-1-expected.html: Added.
* fast/text/whitespace/trailing-space-before-empty-span-1.html: A test
    with a span whose text ends with a single span. A following span
    is empty but requires a line box (because it has some padding).
    The second span should be rendered.
* fast/text/whitespace/trailing-space-before-empty-span-2-expected.html: Added.
* fast/text/whitespace/trailing-space-before-empty-span-2.html: Same
    test as trailing-space-before-empty-span-1.html except that second
    span contains whitespace only text.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148027 268f45cc-cd09-0410-ab3c-d52691b4dbfc