Merge 109543 - REGRESSION (r104060): Page contents not painted if inserting a new stylesheet and te…

Merge 109543 - REGRESSION (r104060): Page contents not painted if inserting a new stylesheet and temporary body node
https://bugs.webkit.org/show_bug.cgi?id=76590

Reviewed by Maciej Stachowiak.

Source/WebCore: 

Test: fast/css/pending-stylesheet-repaint.html
        
If there has been a style recalc with a pending stylesheet, the forced repaint will need to be triggered even
if the stylesheet doesn't affect the rendering. Otherwise we may end up never painting at all.

* dom/Document.cpp:
(WebCore::Document::styleSelectorChanged):

LayoutTests: 

* fast/css/pending-stylesheet-repaint-expected.png: Added.
* fast/css/pending-stylesheet-repaint-expected.txt: Added.
* fast/css/pending-stylesheet-repaint.html: Added.



TBR=antti@apple.com
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=109960