REGRESSION (r154614): Setting the document scroll position isn't symmetric; can successfully set document.body.scrollTop, but can only read from document.documentElement.scrollTop
https://bugs.webkit.org/show_bug.cgi?id=121876

Patch by Gurpreet Kaur <k.gurpreet@samsung.com> on 2013-09-28
Reviewed by Darin Adler.

Source/WebCore:

Non-Quirks mode should set/get scrolltop/scrollleft through
document.documentElement.scrollTop/document.documentElement.scrollLeft
Quirks mode should set/get scrolltop/scrollleft through
document.body.scrollTop/document.body.scrollLeft.

Tests: fast/dom/Element/body-scrollLeft-Quirks.html
       fast/dom/Element/body-scrollLeft.html
       fast/dom/Element/body-scrollTop-Quirks.html
       fast/dom/Element/body-scrollTop.html
       fast/dom/Element/documentElement-scrollLeft-Quirks.html
       fast/dom/Element/documentElement-scrollLeft.html
       fast/dom/Element/documentElement-scrollTop-Quirks.html
       fast/dom/Element/documentElement-scrollTop.html

* dom/Element.cpp:
(WebCore::Element::setScrollLeft):
(WebCore::Element::setScrollTop):
* html/HTMLBodyElement.cpp:
(WebCore::HTMLBodyElement::setScrollLeft):
(WebCore::HTMLBodyElement::setScrollTop):
Need to set the scrollTop and scrollLeft after checking if document
is in quirks or non-quirks mode. Incase it is body.scrollLeft/
body.scrollTop set only if document is in quirks mode. If document is
non-quirks mode set documentElement.scrollLeft/documentElement.scrollTop.

LayoutTests:

* fast/dom/Element/body-scrollLeft-Quirks-expected.txt: Added.
* fast/dom/Element/body-scrollLeft-Quirks.html: Added.
* fast/dom/Element/body-scrollLeft-expected.txt: Added.
* fast/dom/Element/body-scrollLeft.html: Added.
* fast/dom/Element/body-scrollTop-Quirks-expected.txt: Added.
* fast/dom/Element/body-scrollTop-Quirks.html: Added.
* fast/dom/Element/body-scrollTop-expected.txt: Added.
* fast/dom/Element/body-scrollTop.html: Added.
* fast/dom/Element/documentElement-scrollLeft-Quirks-expected.txt: Added.
* fast/dom/Element/documentElement-scrollLeft-Quirks.html: Added.
* fast/dom/Element/documentElement-scrollLeft-expected.txt: Added.
* fast/dom/Element/documentElement-scrollLeft.html: Added.
* fast/dom/Element/documentElement-scrollTop-Quirks-expected.txt: Added.
* fast/dom/Element/documentElement-scrollTop-Quirks.html: Added.
* fast/dom/Element/documentElement-scrollTop-expected.txt: Added.
* fast/dom/Element/documentElement-scrollTop.html: Added.
Added test cases for verifying that Non-Quirks mode should set
scrolltop/scrollleft through document.documentElement.scrollTop/
document.documentElement.scrollLeft and Quirks mode should set/get
scrolltop/scrollleft through document.body.scrollTop/document.body.scrollLeft.

* fast/multicol/scrolling-overflow.html:
Rebaselining existing tests as per the new behavior. To set
document.body.scrollLeft document to be in Quirks mode.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@156605 268f45cc-cd09-0410-ab3c-d52691b4dbfc