[New Multicolumn] Avoid freeze if column count is 1 and there's a forced break.

Source/core/rendering/RenderMultiColumnSet.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 119 matching lines @@
         unsigned index = findRunWithTallestColumns();
         LayoutUnit startOffset = index > 0 ? m_contentRuns[index - 1].breakOffset() : LayoutUnit();
         return std::max<LayoutUnit>(m_contentRuns[index].columnLogicalHeight(startOffset), m_minimumColumnHeight);
     }
 
     if (columnCount() <= computedColumnCount()) {
         // With the current column height, the content fits without creating overflowing columns. We're done.
         return m_computedColumnHeight;
     }
 
-    if (forcedBreaksCount() > 1 && forcedBreaksCount() >= computedColumnCount()) {
+    if (forcedBreaksCount() >= computedColumnCount()) {
         // Too many forced breaks to allow any implicit breaks. Initial balancing should already
         // have set a good height. There's nothing more we should do.
         return m_computedColumnHeight;
     }
 
     // If the initial guessed column height wasn't enough, stretch it now. Stretch by the lowest
     // amount of space shortage found during layout.
 
     ASSERT(m_minSpaceShortage > 0); // We should never _shrink_ the height!
     ASSERT(m_minSpaceShortage != RenderFlowThread::maxLogicalHeight()); // If this happens, we probably have a bug.
@@ skipping 433 matching lines @@
         fragments.append(fragment);
     }
 }
 
 const char* RenderMultiColumnSet::renderName() const
 {
     return "RenderMultiColumnSet";
 }
 
 }