Background doesn't fully repaint when body has margins.
https://bugs.webkit.org/show_bug.cgi?id=119033

Reviewed by Simon Fraser.

Ensure that background-color changes do not leave unpainted areas when
body has margins.

Both <body> and <html> background-color get propagated up to the viewport.
If <body> has background-color attribute set, while <html> doesn't, the color is
applied not only on the <body> but on both the <html> and the viewport. However,
it's not enough to mark the RenderView dirty because with tiles backing on,
there could be areas outside of the viewport that need repaint. By marking
the RenderView's graphics layer dirty instead, we ensure that all the related
tiles get marked dirty too and the new background color covers all areas.

Manual test added. When forcing top-level composition on (even with embedded iframe to
make sure we don't do paintsIntoWindow rendering), the test case execution changes so much,
that the repaint rects don't reflect the functionality difference anymore.

.:

Reviewed by Simon Fraser.

* ManualTests/compositing/background-color-change-on-body-with-margin.html: Added.

Source/WebCore:

* page/FrameView.cpp:
(WebCore::FrameView::reset):
(WebCore::FrameView::layout):
* page/FrameView.h:
(WebCore::FrameView::needsFullRepaint):
* rendering/RenderBox.cpp:
(WebCore::RenderBox::styleWillChange):
* rendering/RenderObjectChildList.cpp:
(WebCore::RenderObjectChildList::removeChildNode):
* rendering/RenderView.cpp:
(WebCore::RenderView::repaintRootContents):
(WebCore::RenderView::repaintViewAndCompositedLayers):
* rendering/RenderView.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153701 268f45cc-cd09-0410-ab3c-d52691b4dbfc