<rdar://problem/10246137> Duplicate ::after content when both ::before and ::after...

<rdar://problem/10246137> Duplicate ::after content when both ::before and ::after are styled as table parts

Reviewed by Sam Weinig.

Source/WebCore:

Test: fast/css-generated-content/table-parts-before-and-after.html

* rendering/RenderObject.cpp:
(WebCore::RenderObject::addChild): Prevented table part childern after a ::before table from being merged
into it.
* rendering/RenderTable.cpp:
(WebCore::RenderTable::addChild): Prevented children after a ::before table section from being merged
into it.

LayoutTests:

* fast/css-generated-content/table-parts-before-and-after-expected.png: Added.
* fast/css-generated-content/table-parts-before-and-after-expected.txt: Added.
* fast/css-generated-content/table-parts-before-and-after.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@97114 268f45cc-cd09-0410-ab3c-d52691b4dbfc