r148197 broke the GTK+ build
https://bugs.webkit.org/show_bug.cgi?id=114525

Reviewed by Anders Carlsson.

Re-add the ENABLE(SCROLLING_THREAD) guards to scrolling thread files
and extend them with USE(COORDINATED_GRAPHICS). This code is unused
by other configurations currently.

* page/scrolling/ScrollingStateFixedNode.cpp: Re-add guards.
* page/scrolling/ScrollingStateFixedNode.h: Ditto.
* page/scrolling/ScrollingStateNode.cpp: Ditto.
* page/scrolling/ScrollingStateNode.h: Ditto.
* page/scrolling/ScrollingStateScrollingNode.cpp: Ditto.
* page/scrolling/ScrollingStateScrollingNode.h: Ditto.
* page/scrolling/ScrollingStateStickyNode.cpp: Ditto.
* page/scrolling/ScrollingStateStickyNode.h: Ditto.
* page/scrolling/ScrollingStateTree.cpp: Ditto.
* page/scrolling/ScrollingStateTree.h: Ditto.
* page/scrolling/mac/ScrollingStateNodeMac.mm: Ditto.
* page/scrolling/mac/ScrollingStateScrollingNodeMac.mm: Ditto.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148298 268f45cc-cd09-0410-ab3c-d52691b4dbfc