[CSS Regions][CSS Exclusions] shape-inside on regions should respect positioned shapes and overflow
https://bugs.webkit.org/show_bug.cgi?id=116252

Reviewed by David Hyatt.

Regions should respect shape-inside properties which have specified top offset. Since the content which overflows from the
shape should be pushed after the content box (for details check out r148975), I implemented  overflowthe behavior for simple
cases when you have only one region. I'm going to implement it for additional regions in a follow up patch.

Tests: fast/regions/shape-inside/shape-inside-on-regions-block-content-basic-overflow-shape-top-offset.html
       fast/regions/shape-inside/shape-inside-on-regions-inline-content-basic-overflow-shape-top-offset.html

Source/WebCore:

* rendering/RenderBlockLineLayout.cpp:
(WebCore::RenderBlock::updateLineBoundariesForExclusions): Handle the flow thread case, push the overflowing content after the
content box. Respect existing shape-inside on region tests.
(WebCore::RenderBlock::layoutRunsAndFloatsInRange): Set the correct logical top position for the shape-inside in
the case of regions. Respect the region's margins and paddings.

LayoutTests:

* fast/regions/shape-inside/shape-inside-on-regions-block-content-basic-overflow-shape-top-offset-expected.html: Added.
* fast/regions/shape-inside/shape-inside-on-regions-block-content-basic-overflow-shape-top-offset.html: Added.
* fast/regions/shape-inside/shape-inside-on-regions-inline-content-basic-overflow-shape-top-offset-expected.html: Added.
* fast/regions/shape-inside/shape-inside-on-regions-inline-content-basic-overflow-shape-top-offset.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150375 268f45cc-cd09-0410-ab3c-d52691b4dbfc