Behave more normally for content taller than the fragmentainer it's in.

Source/core/layout/LayoutFlowThread.cpp

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 21 matching lines @@
 #include "core/layout/LayoutFlowThread.h"
 
 #include "core/layout/LayoutMultiColumnSet.h"
 #include "core/layout/LayoutView.h"
 
 namespace blink {
 
 LayoutFlowThread::LayoutFlowThread()
     : LayoutBlockFlow(nullptr)
     , m_columnSetsInvalidated(false)
-    , m_columnSetsHaveUniformLogicalHeight(true)
     , m_pageLogicalSizeChanged(false)
 {
 }
 
 void LayoutFlowThread::removeColumnSetFromThread(LayoutMultiColumnSet* columnSet)
 {
     ASSERT(columnSet);
     m_multiColumnSetList.remove(columnSet);
     invalidateColumnSets();
     // Clear the interval tree right away, instead of leaving it around with dead objects. Not that
@@ skipping 11 matching lines @@
         return;
     }
 
     setNeedsLayoutAndFullPaintInvalidation(LayoutInvalidationReason::ColumnsChanged);
 
     m_columnSetsInvalidated = true;
 }
 
 void LayoutFlowThread::validateColumnSets()
 {
-    if (m_columnSetsInvalidated) {
-        m_columnSetsInvalidated = false;
-        m_columnSetsHaveUniformLogicalHeight = true;
-
-        if (hasColumnSets()) {
-            LayoutUnit previousLogicalHeight = 0;
-            bool firstVisited = false;
-
-            for (auto* columnSet : m_multiColumnSetList) {
-                LayoutUnit currentLogicalHeight = columnSet->pageLogicalHeight();
-
-                if (!firstVisited) {
-                    firstVisited = true;
-                } else {
-                    if (m_columnSetsHaveUniformLogicalHeight && previousLogicalHeight != currentLogicalHeight)
-                        m_columnSetsHaveUniformLogicalHeight = false;
-                }
-
-                previousLogicalHeight = currentLogicalHeight;
-            }
-        }
-    }
-
+    m_columnSetsInvalidated = false;
     updateLogicalWidth(); // Called to get the maximum logical width for the columnSet.
     generateColumnSetIntervalTree();
 }
 
 void LayoutFlowThread::mapRectToPaintInvalidationBacking(const LayoutBoxModelObject* paintInvalidationContainer, LayoutRect& rect, const PaintInvalidationState* paintInvalidationState) const
 {
     ASSERT(paintInvalidationContainer != this); // A flow thread should never be an invalidation container.
     // |rect| is a layout rectangle, where the block direction coordinate is flipped for writing
     // mode. fragmentsBoundingBox(), on the other hand, works on physical rectangles, so we need to
     // flip the rectangle before and after calling it.
@@ skipping 95 matching lines @@
 
 void LayoutFlowThread::MultiColumnSetSearchAdapter::collectIfNeeded(const MultiColumnSetInterval& interval)
 {
     if (m_result)
         return;
     if (interval.low() <= m_offset && interval.high() > m_offset)
         m_result = interval.data();
 }
 
 } // namespace blink