https://bugs.webkit.org/show_bug.cgi?id=119979

Reviewed by David Hyatt.

Source/WebCore:

If a float has a self-collapsing ancestor with clearance then it needs to respect
that clearance when placing itself on the line.

Test: fast/block/margin-collapse/self-collapsing-block-with-float-descendant.html

* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::marginOffsetForSelfCollapsingBlock):
* rendering/RenderBlock.h:
* rendering/RenderBlockLineLayout.cpp:
(WebCore::RenderBlock::LineBreaker::skipLeadingWhitespace):
* rendering/RenderBox.h:
(WebCore::RenderBox::previousInFlowSiblingBox):

LayoutTests:

* fast/block/margin-collapse/self-collapsing-block-with-float-descendant-expected.html: Added.
* fast/block/margin-collapse/self-collapsing-block-with-float-descendant.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154399 268f45cc-cd09-0410-ab3c-d52691b4dbfc