Compute the normal flow list on the fly

Source/core/paint/DeprecatedPaintLayer.cpp

Index: Source/core/paint/DeprecatedPaintLayer.cpp
diff --git a/Source/core/paint/DeprecatedPaintLayer.cpp b/Source/core/paint/DeprecatedPaintLayer.cpp
index b76ef401ce7d5e81619862e1ec501a8019b035d5..beca696c76f5b90321c8731d05c1434d46e5dc37 100644
--- a/Source/core/paint/DeprecatedPaintLayer.cpp
+++ b/Source/core/paint/DeprecatedPaintLayer.cpp
@@ -1140,8 +1140,10 @@ void DeprecatedPaintLayer::addChild(DeprecatedPaintLayer* child, DeprecatedPaint
 
     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
@@ -1168,8 +1170,11 @@ DeprecatedPaintLayer* DeprecatedPaintLayer::removeChild(DeprecatedPaintLayer* ol
     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
@@ -2419,7 +2424,7 @@ bool DeprecatedPaintLayer::backgroundIsKnownToBeOpaqueInRect(const LayoutRect& l
     // 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,