Refactor avoidsFloats() to reflect CSS2.1 spec more clearly

Source/core/rendering/RenderBlockFlow.cpp

Index: Source/core/rendering/RenderBlockFlow.cpp
diff --git a/Source/core/rendering/RenderBlockFlow.cpp b/Source/core/rendering/RenderBlockFlow.cpp
index 79571ad4b80534c6cc8771980d42f5d73a334acc..19f6682e586c6da18d734795959ba0163ca6a674 100644
--- a/Source/core/rendering/RenderBlockFlow.cpp
+++ b/Source/core/rendering/RenderBlockFlow.cpp
@@ -899,7 +899,7 @@ void RenderBlockFlow::rebuildFloatsFromIntruding()
     }
 
     // Inline blocks are covered by the isReplaced() check in the avoidFloats method.
-    if (avoidsFloats() || isDocumentElement() || isRenderView() || isFloatingOrOutOfFlowPositioned() || isTableCell()) {
+    if (avoidsOrIgnoresFloats() || isRenderView()) {
         if (m_floatingObjects) {
             m_floatingObjects->clear();
         }
@@ -929,7 +929,7 @@ void RenderBlockFlow::rebuildFloatsFromIntruding()
     RenderBlockFlow* parentBlockFlow = toRenderBlockFlow(parent());
     bool parentHasFloats = false;
     RenderObject* prev = previousSibling();
-    while (prev && (!prev->isBox() || !prev->isRenderBlock() || toRenderBlock(prev)->avoidsFloats() || toRenderBlock(prev)->createsBlockFormattingContext())) {
+    while (prev && (!prev->isBox() || !prev->isRenderBlock() || toRenderBlock(prev)->avoidsOrIgnoresFloats())) {
         if (prev->isFloating())
             parentHasFloats = true;
         prev = prev->previousSibling();
@@ -1838,7 +1838,7 @@ void RenderBlockFlow::markSiblingsWithFloatsForLayout(RenderBox* floatToRemove)
     FloatingObjectSetIterator end = floatingObjectSet.end();
 
     for (RenderObject* next = nextSibling(); next; next = next->nextSibling()) {
-        if (!next->isRenderBlockFlow() || next->isFloatingOrOutOfFlowPositioned() || toRenderBlockFlow(next)->avoidsFloats())
+        if (!next->isRenderBlockFlow() || avoidsOrIgnoresFloats())
             continue;
 
         RenderBlockFlow* nextBlock = toRenderBlockFlow(next);
@@ -1917,7 +1917,7 @@ void RenderBlockFlow::createFloatingObjects()
 void RenderBlockFlow::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
 {
     RenderStyle* oldStyle = style();
-    s_canPropagateFloatIntoSibling = oldStyle ? !isFloatingOrOutOfFlowPositioned() && !avoidsFloats() : false;
+    s_canPropagateFloatIntoSibling = oldStyle ? !avoidsOrIgnoresFloats() : false;

[rhogan, 2014/11/11 19:17:13]

I had !createsBlockFormattingContext() here; which is consistent with the logic
elsewhere. This seems like a good candidate for the cause of the crash in bug
388757 (which I can't recreate).

     if (oldStyle && parent() && diff.needsFullLayout() && oldStyle->position() != newStyle.position()
         && containsFloats() && !isFloating() && !isOutOfFlowPositioned() && newStyle.hasOutOfFlowPosition())
             markAllDescendantsWithFloatsForLayout();
@@ -1933,7 +1933,7 @@ void RenderBlockFlow::styleDidChange(StyleDifference diff, const RenderStyle* ol
     // blocks, then we need to find the top most parent containing that overhanging float and
     // then mark its descendants with floats for layout and clear all floats from its next
     // sibling blocks that exist in our floating objects list. See bug 56299 and 62875.
-    bool canPropagateFloatIntoSibling = !isFloatingOrOutOfFlowPositioned() && !avoidsFloats();
+    bool canPropagateFloatIntoSibling = !avoidsOrIgnoresFloats();
     if (diff.needsFullLayout() && s_canPropagateFloatIntoSibling && !canPropagateFloatIntoSibling && hasOverhangingFloats()) {
         RenderBlockFlow* parentBlockFlow = this;
         const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
@@ -2710,13 +2710,6 @@ void RenderBlockFlow::setPaginationStrut(LayoutUnit strut)
     m_rareData->m_paginationStrut = strut;
 }
 
-bool RenderBlockFlow::avoidsFloats() const
-{
-    // Floats can't intrude into our box if we have a non-auto column count or width.
-    // Note: we need to use RenderBox::avoidsFloats here since RenderBlock::avoidsFloats is always true.
-    return RenderBox::avoidsFloats() || !style()->hasAutoColumnCount() || !style()->hasAutoColumnWidth();
-}
-
 LayoutUnit RenderBlockFlow::logicalLeftSelectionOffset(const RenderBlock* rootBlock, LayoutUnit position) const
 {
     LayoutUnit logicalLeft = logicalLeftOffsetForLine(position, false);