Revert "Make compositingState explicit (re-land #2 with bogus ASSERT removed)"

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 1241 matching lines @@
 {
     for (Frame* frame = m_frame.get(); frame; frame = frame->tree()->traverseNext(m_frame.get())) {
         if (FrameView* view = frame->view())
             view->setCanBlitOnScroll(!view->useSlowRepaints());
     }
 }
 
 bool FrameView::contentsInCompositedLayer() const
 {
     RenderView* renderView = this->renderView();
-    if (renderView && renderView->compositingState() == PaintsIntoOwnBacking) {
+    if (renderView && renderView->isComposited()) {
         GraphicsLayer* layer = renderView->layer()->compositedLayerMapping()->mainGraphicsLayer();
         if (layer && layer->drawsContent())
             return true;
     }
 
     return false;
 }
 
 void FrameView::setCannotBlitToWindow()
 {
@@ skipping 96 matching lines @@
     ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
     for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
         RenderObject* renderer = *it;
         if (!renderer->style()->hasViewportConstrainedPosition())
             continue;
 
         // Fixed items should always have layers.
         ASSERT(renderer->hasLayer());
         RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();
 
-        // Layers that paint into their ancestor or into a grouped backing will still need
-        // to apply a repaint invalidation. If the layer paints into its own backing, then
-        // it does not need repainting just to scroll.
-        if (layer->compositingState() == PaintsIntoOwnBacking)
+        // Composited layers may still actually paint into their ancestor.
+        // If that happens, the viewport constrained object needs to be
+        // repainted on scroll.
+        if (layer->isComposited() && !layer->compositedLayerMapping()->paintsIntoCompositedAncestor())
             continue;
 
         if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
             || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent) {
             // Don't invalidate for invisible fixed layers.
             continue;
         }
 
         if (layer->hasAncestorWithFilterOutsets()) {
             // If the fixed layer has a blur/drop-shadow filter applied on at least one of its parents, we cannot
@@ skipping 2065 matching lines @@
 void FrameView::setLayoutSizeInternal(const IntSize& size)
 {
     if (m_layoutSize == size)
         return;
 
     m_layoutSize = size;
     contentsResized();
 }
 
 } // namespace WebCore