Revert of Fix shouldPaint issue when a composited floating iframe becomes non-self-painting

third_party/WebKit/Source/core/paint/PaintLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 139 matching lines @@
       m_needsPaintPhaseDescendantOutlines(false),
       m_previousPaintPhaseDescendantOutlinesWasEmpty(false),
       m_needsPaintPhaseFloat(false),
       m_previousPaintPhaseFloatWasEmpty(false),
       m_needsPaintPhaseDescendantBlockBackgrounds(false),
       m_previousPaintPhaseDescendantBlockBackgroundsWasEmpty(false),
       m_hasDescendantWithClipPath(false),
       m_hasNonIsolatedDescendantWithBlendMode(false),
       m_hasAncestorWithClipPath(false),
       m_hasRootScrollerAsDescendant(false),
-      m_selfPaintingStatusChanged(false),
       m_layoutObject(layoutObject),
       m_parent(0),
       m_previous(0),
       m_next(0),
       m_first(0),
       m_last(0),
       m_staticInlinePosition(0),
       m_staticBlockPosition(0),
       m_ancestorOverflowLayer(nullptr) {
   updateStackingNode();
@@ skipping 1339 matching lines @@
   } else {
     // The ancestor layer is also inside the pagination layer, so we need to
     // subtract the visual distance from the ancestor layer to the pagination
     // layer.
     offset.moveBy(-ancestorLayer->visualOffsetFromAncestor(paginationLayer));
   }
   return offset;
 }
 
 void PaintLayer::didUpdateNeedsCompositedScrolling() {
+  bool wasSelfPaintingLayer = isSelfPaintingLayer();
   updateSelfPaintingLayer();
+
+  // If the floating object becomes non-self-painting, so some ancestor should
+  // paint it; if it becomes self-painting, it should paint itself and no
+  // ancestor should paint it.
+  if (wasSelfPaintingLayer != isSelfPaintingLayer() &&
+      m_layoutObject->isFloating())
+    LayoutBlockFlow::setAncestorShouldPaintFloatingObject(*layoutBox());
 }
 
 void PaintLayer::updateStackingNode() {
   DCHECK(!m_stackingNode);
   if (requiresStackingNode())
     m_stackingNode = WTF::makeUnique<PaintLayerStackingNode>(this);
   else
     m_stackingNode = nullptr;
 }
 
@@ skipping 1248 matching lines @@
     LayoutRect childLocalRect(localRect);
     childLayer->convertToLayerCoords(this, childOffset);
     childLocalRect.moveBy(-childOffset);
 
     if (childLayer->backgroundIsKnownToBeOpaqueInRect(childLocalRect))
       return true;
   }
   return false;
 }
 
+bool PaintLayer::isSelfPaintingLayerForIntrinsicOrScrollingReasons() const {
+  return layoutObject()->layerTypeRequired() == NormalPaintLayer ||
+         (m_scrollableArea && m_scrollableArea->hasOverlayScrollbars()) ||
+         needsCompositedScrolling();
+}
+
 bool PaintLayer::shouldBeSelfPaintingLayer() const {
   if (layoutObject()->isLayoutPart() &&
       toLayoutPart(layoutObject())->requiresAcceleratedCompositing())
     return true;
+  return isSelfPaintingLayerForIntrinsicOrScrollingReasons();
+}
 
-  return layoutObject()->layerTypeRequired() == NormalPaintLayer ||
-         (m_scrollableArea && m_scrollableArea->hasOverlayScrollbars()) ||
-         needsCompositedScrolling();
+bool PaintLayer::isSelfPaintingOnlyBecauseIsCompositedPart() const {
+  return shouldBeSelfPaintingLayer() &&
+         !isSelfPaintingLayerForIntrinsicOrScrollingReasons();
 }
 
 void PaintLayer::updateSelfPaintingLayer() {
   bool isSelfPaintingLayer = shouldBeSelfPaintingLayer();
   if (this->isSelfPaintingLayer() == isSelfPaintingLayer)
     return;
 
   m_isSelfPaintingLayer = isSelfPaintingLayer;
-  m_selfPaintingStatusChanged = true;
 
   if (PaintLayer* parent = this->parent()) {
     parent->dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();
 
     if (PaintLayer* enclosingSelfPaintingLayer =
             parent->enclosingSelfPaintingLayer()) {
       if (isSelfPaintingLayer)
         mergeNeedsPaintPhaseFlagsFrom(*enclosingSelfPaintingLayer);
       else
         enclosingSelfPaintingLayer->mergeNeedsPaintPhaseFlagsFrom(*this);
@@ skipping 405 matching lines @@
 }
 
 void showLayerTree(const blink::LayoutObject* layoutObject) {
   if (!layoutObject) {
     LOG(INFO) << "Cannot showLayerTree. Root is (nil)";
     return;
   }
   showLayerTree(layoutObject->enclosingLayer());
 }
 #endif