Need to consider the need for a soft break even when inserting a forced break.

third_party/WebKit/Source/core/layout/LayoutBlockFlow.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003-2013 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ skipping 347 matching lines @@
     LayoutSize accumulateInFlowPositionOffsets() const override;
 
 private:
     bool layoutBlockFlow(bool relayoutChildren, LayoutUnit& pageLogicalHeight, SubtreeLayoutScope&);
     void layoutBlockChildren(bool relayoutChildren, SubtreeLayoutScope&, LayoutUnit beforeEdge, LayoutUnit afterEdge);
 
     void markDescendantsWithFloatsForLayoutIfNeeded(LayoutBlockFlow& child, LayoutUnit newLogicalTop, LayoutUnit previousFloatLogicalBottom);
     bool positionAndLayoutOnceIfNeeded(LayoutBox& child, LayoutUnit newLogicalTop, BlockChildrenLayoutInfo&);
 
     // Handle breaking policy before the child, and insert a forced break in front of it if needed.
-    // Returns true if a forced break was inserted.
-    bool insertForcedBreakBeforeChildIfNeeded(LayoutBox& child, BlockChildrenLayoutInfo&);
+    void insertForcedBreakBeforeChildIfNeeded(LayoutBox& child, BlockChildrenLayoutInfo&);
 
     void layoutBlockChild(LayoutBox& child, BlockChildrenLayoutInfo&);
     void adjustPositionedBlock(LayoutBox& child, const BlockChildrenLayoutInfo&);
     void adjustFloatingBlock(const MarginInfo&);
 
     LayoutPoint computeLogicalLocationForFloat(const FloatingObject&, LayoutUnit logicalTopOffset) const;
 
     void removeFloatingObject(LayoutBox*);
     void removeFloatingObjectsBelow(FloatingObject*, int logicalOffset);
 
@@ skipping 283 matching lines @@
 
 // END METHODS DEFINED IN LayoutBlockFlowLine
 
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlockFlow, isLayoutBlockFlow());
 
 } // namespace blink
 
 #endif // LayoutBlockFlow_h