Compute the normal flow list on the fly

Source/core/paint/DeprecatedPaintLayer.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>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 1122 matching lines @@
         child->setNextSibling(beforeChild);
         ASSERT(beforeChild != child);
     } else {
         setLastChild(child);
     }
 
     child->m_parent = this;
 
     setNeedsCompositingInputsUpdate();
 
-    if (!child->stackingNode()->isTreatedAsStackingContextForPainting())
-        m_stackingNode->dirtyNormalFlowList();
+    if (!child->stackingNode()->isTreatedAsStackingContextForPainting()) {

[dsinclair, 2015/06/24 15:22:41]

Any reason to not have this as a single if statement?

if (!child->stackingNode()->isTreatedAsStackingContextForPainting() &&
!layoutObject->documentBeingDestroyed())
  compositor()->setNeedsCompositingUpdate(CompositingUpdateRebuildTree);

Same below.

[Julien - ping for review, 2015/06/24 16:51:57]

None really.
Done and done.

+        if (!layoutObject()->documentBeingDestroyed())
+            compositor()->setNeedsCompositingUpdate(CompositingUpdateRebuildTree);
+    }
 
     if (child->stackingNode()->isTreatedAsStackingContextForPainting() || child->firstChild()) {
         // Dirty the z-order list in which we are contained. The ancestorStackingContextNode() can be null in the
         // case where we're building up generated content layers. This is ok, since the lists will start
         // off dirty in that case anyway.
         child->stackingNode()->dirtyStackingContextZOrderLists();
     }
 
     dirtyAncestorChainVisibleDescendantStatus();
     dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();
 
     child->updateDescendantDependentFlags();
 }
 
 DeprecatedPaintLayer* DeprecatedPaintLayer::removeChild(DeprecatedPaintLayer* oldChild)
 {
     if (oldChild->previousSibling())
         oldChild->previousSibling()->setNextSibling(oldChild->nextSibling());
     if (oldChild->nextSibling())
         oldChild->nextSibling()->setPreviousSibling(oldChild->previousSibling());
 
     if (m_first == oldChild)
         m_first = oldChild->nextSibling();
     if (m_last == oldChild)
         m_last = oldChild->previousSibling();
 
-    if (!oldChild->stackingNode()->isTreatedAsStackingContextForPainting())
-        m_stackingNode->dirtyNormalFlowList();
+    if (!oldChild->stackingNode()->isTreatedAsStackingContextForPainting()) {
+        if (!layoutObject()->documentBeingDestroyed())
+            compositor()->setNeedsCompositingUpdate(CompositingUpdateRebuildTree);
+    }
+
     if (oldChild->stackingNode()->isTreatedAsStackingContextForPainting() || oldChild->firstChild()) {
         // Dirty the z-order list in which we are contained.  When called via the
         // reattachment process in removeOnlyThisLayer, the layer may already be disconnected
         // from the main layer tree, so we need to null-check the
         // |stackingContext| value.
         oldChild->stackingNode()->dirtyStackingContextZOrderLists();
     }
 
     if (layoutObject()->style()->visibility() != VISIBLE)
         dirtyVisibleContentStatus();
@@ skipping 1229 matching lines @@
     if (paintsWithFilters() && layoutObject()->style()->filter().hasFilterThatAffectsOpacity())
         return false;
 
     // FIXME: Handle simple transforms.
     if (paintsWithTransform(PaintBehaviorNormal))
         return false;
 
     // FIXME: Remove this check.
     // This function should not be called when layer-lists are dirty.
     // It is somehow getting triggered during style update.
-    if (m_stackingNode->zOrderListsDirty() || m_stackingNode->normalFlowListDirty())
+    if (m_stackingNode->zOrderListsDirty())
         return false;
 
     // FIXME: We currently only check the immediate layoutObject,
     // which will miss many cases.
     if (layoutObject()->backgroundIsKnownToBeOpaqueInRect(localRect))
         return true;
 
     // We can't consult child layers if we clip, since they might cover
     // parts of the rect that are clipped out.
     if (layoutObject()->hasOverflowClip())
@@ skipping 322 matching lines @@
 
 void showLayerTree(const blink::LayoutObject* layoutObject)
 {
     if (!layoutObject) {
         fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
         return;
     }
     showLayerTree(layoutObject->enclosingLayer());
 }
 #endif