[chromium] Turn off ScrollbarLayerChromium for Windows due to bad alpha values
authorenne@google.com <enne@google.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Tue, 17 Jul 2012 01:24:45 +0000 (01:24 +0000)
committerenne@google.com <enne@google.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Tue, 17 Jul 2012 01:24:45 +0000 (01:24 +0000)
commite61bd0c4a9c1bc2540407bf92370e6fb2e90cbc8
tree6143a60993a8ebdf5922115686345f73e2fb3db8
parentb11f4957a7bcf7696b48294ceb3f2a5308023eea
[chromium] Turn off ScrollbarLayerChromium for Windows due to bad alpha values
https://bugs.webkit.org/show_bug.cgi?id=91438

Reviewed by Kenneth Russell.

r120509 turned on blending for scrollbar thumbs. Unfortunately for
Windows XP scrollbar thumbs, their alpha channel is bogus and so the
thumb ends up being completely transparent. This should ultimately be
fixed in Chromium theme code, but in the meantime this patch turns
off the use of ScrollbarLayerChromium.

This change makes Windows scrollbars fall back to using normal
ContentLayerChromiums and being painted all in one layer on the main
thread rather than being painted separately and composited on the
compositor thread.

* page/scrolling/chromium/ScrollingCoordinatorChromium.cpp:
(WebCore::createScrollbarLayer):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@122791 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Source/WebCore/ChangeLog
Source/WebCore/page/scrolling/chromium/ScrollingCoordinatorChromium.cpp