Recalculate column heights as part of column set layout.

third_party/WebKit/Source/core/layout/LayoutMultiColumnFlowThread.cpp

 /*
  * Copyright (C) 2012 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 19 matching lines @@
 #include "core/layout/LayoutView.h"
 #include "core/layout/MultiColumnFragmentainerGroup.h"
 #include "core/layout/ViewFragmentationContext.h"
 
 namespace blink {
 
 LayoutMultiColumnFlowThread::LayoutMultiColumnFlowThread()
     : m_lastSetWorkedOn(nullptr)
     , m_columnCount(1)
     , m_columnHeightAvailable(0)
-    , m_inBalancingPass(false)
-    , m_needsColumnHeightsRecalculation(false)
+    , m_columnHeightsChanged(false)
     , m_progressionIsInline(true)
     , m_isBeingEvacuated(false)
 {
     setIsInsideFlowThread(true);
 }
 
 LayoutMultiColumnFlowThread::~LayoutMultiColumnFlowThread()
 {
 }
 
@@ skipping 295 matching lines @@
     return adapter.result();
 }
 
 void LayoutMultiColumnFlowThread::layoutColumns(SubtreeLayoutScope& layoutScope)
 {
     // Since we ended up here, it means that the multicol container (our parent) needed
     // layout. Since contents of the multicol container are diverted to the flow thread, the flow
     // thread needs layout as well.
     layoutScope.setChildNeedsLayout(this);
 
-    m_needsColumnHeightsRecalculation = false;
-
     m_blockOffsetInEnclosingFragmentationContext = enclosingFragmentationContext() ? multiColumnBlockFlow()->offsetFromLogicalTopOfFirstPage() : LayoutUnit();
 
     for (LayoutBox* columnBox = firstMultiColumnBox(); columnBox; columnBox = columnBox->nextSiblingMultiColumnBox()) {
         if (!columnBox->isLayoutMultiColumnSet()) {
             ASSERT(columnBox->isLayoutMultiColumnSpannerPlaceholder()); // no other type is expected.
-            m_needsColumnHeightsRecalculation = true;
             continue;
         }
         LayoutMultiColumnSet* columnSet = toLayoutMultiColumnSet(columnBox);
         layoutScope.setChildNeedsLayout(columnSet);
-        if (!m_inBalancingPass) {
+        if (!m_columnHeightsChanged) {
             // This is the initial layout pass. We need to reset the column height, because contents
             // typically have changed.
             columnSet->resetColumnHeight();
         }
-        if (!m_needsColumnHeightsRecalculation)
-            m_needsColumnHeightsRecalculation = columnSet->heightIsAuto();
         // Since column sets are regular block flow objects, and their position is changed in
         // regular block layout code (with no means for the multicol code to notice unless we add
         // hooks there), store the previous position now. If it changes in the imminent layout
         // pass, we may have to rebalance its columns.
         columnSet->storeOldPosition();
     }
 
+    m_columnHeightsChanged = false;
     invalidateColumnSets();
     layout();
-}
-
-bool LayoutMultiColumnFlowThread::recalculateColumnHeights()
-{
-    // All column sets that needed layout have now been laid out, so we can finally validate them.
     validateColumnSets();
-
-    if (!m_needsColumnHeightsRecalculation)
-        return false;
-
-    // Column heights may change here because of balancing. We may have to do multiple layout
-    // passes, depending on how the contents is fitted to the changed column heights. In most
-    // cases, laying out again twice or even just once will suffice. Sometimes we need more
-    // passes than that, though, but the number of retries should not exceed the number of
-    // columns, unless we have a bug.
-    bool needsRelayout = false;
-    for (LayoutMultiColumnSet* multicolSet = firstMultiColumnSet(); multicolSet; multicolSet = multicolSet->nextSiblingMultiColumnSet())
-        needsRelayout |= multicolSet->recalculateColumnHeight();
-
-    if (needsRelayout)
-        setChildNeedsLayout(MarkOnlyThis);
-
-    m_inBalancingPass = needsRelayout;
-    return needsRelayout;
 }
 
 void LayoutMultiColumnFlowThread::columnRuleStyleDidChange()
 {
     for (LayoutMultiColumnSet* columnSet = firstMultiColumnSet(); columnSet; columnSet = columnSet->nextSiblingMultiColumnSet())
         columnSet->setShouldDoFullPaintInvalidation(PaintInvalidationStyleChange);
 }
 
 bool LayoutMultiColumnFlowThread::removeSpannerPlaceholderIfNoLongerValid(LayoutBox* spannerObjectInFlowThread)
 {
@@ skipping 530 matching lines @@
     // the "mayBe"), if we're in an out-of-flow subtree and have an outer multicol container that
     // doesn't affect us, but that's okay. We'll discover that further down the road when trying to
     // locate our enclosing flow thread for real.
     bool mayBeNested = multiColumnBlockFlow()->isInsideFlowThread() || view()->fragmentationContext();
     if (!mayBeNested)
         return;
     appendNewFragmentainerGroupIfNeeded(logicalTopInFlowThreadAfterPagination);
 }
 
 }