https://bugs.webkit.org/show_bug.cgi?id=72002

Patch by Grzegorz Czajkowski <g.czajkowski@samsung.com> on 2012-01-10
Reviewed by Andreas Kling.

Adds NULL checks to setting object where it's required.
Generally WebCore checks NULL which may be returned from setting object obtained
on frame or document but in some cases these are skipped. These checks are not
needed to setting's access on page object.

* html/HTMLCanvasElement.cpp:
(WebCore::HTMLCanvasElement::shouldAccelerate):
* loader/DocumentLoader.cpp:
(WebCore::DocumentLoader::scheduleArchiveLoad):
* loader/SubframeLoader.cpp:
(WebCore::SubframeLoader::requestPlugin):
* loader/appcache/ApplicationCacheGroup.cpp:
(WebCore::ApplicationCacheGroup::selectCache):
(WebCore::ApplicationCacheGroup::selectCacheWithoutManifestURL):
* page/DragController.cpp:
(WebCore::DragController::draggableNode):
* page/EventHandler.cpp:
(WebCore::EventHandler::handleMouseReleaseEvent):
* page/FocusController.cpp:
(WebCore::FocusController::advanceFocusInDocumentOrder):
* rendering/RenderFrameSet.cpp:
(WebCore::RenderFrameSet::flattenFrameSet):
* rendering/RenderIFrame.cpp:
(WebCore::RenderIFrame::flattenFrame):
* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::updateBacking):
* rendering/RenderText.cpp:
(WebCore::SecureTextTimer::restartWithNewText):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@104552 268f45cc-cd09-0410-ab3c-d52691b4dbfc