[EFL][Qt] REGRESSION(r144787): A fixed element lags when scrolling and wheeling.
https://bugs.webkit.org/show_bug.cgi?id=111829

Patch by Huang Dongsung <luxtella@company100.net> on 2013-03-08
Reviewed by Noam Rosenthal.

Currently, flagsChanged deals with all boolean flags. It introduces this bug
because when another flag (i.e. preserves3D) is changed, fixedToViewport is set
to false. So this patch updates all flags when at least one flag is changed.

In addition, this patch amends isScrollable code to match other flags.

This patch can only be tested manually since there is no automated
testing facilities for in-motion touch.
Test: ManualTests/fixed-position.html
      ManualTests/nested-fixed-position.html

* platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp:
(WebCore::CoordinatedGraphicsLayer::setScrollableArea):
(WebCore::CoordinatedGraphicsLayer::syncLayerState):
* platform/graphics/texmap/coordinated/CoordinatedGraphicsScene.cpp:
(WebCore::CoordinatedGraphicsScene::setLayerState):
* platform/graphics/texmap/coordinated/CoordinatedGraphicsState.h:
(WebCore::CoordinatedGraphicsLayerState::CoordinatedGraphicsLayerState):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145207 268f45cc-cd09-0410-ab3c-d52691b4dbfc