Fix off-by-one (or off-by-one-sixtyfourth) error when checking what a column can hold.

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

 /*
  * 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
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 738 matching lines @@
         // or column, rather than keeping a content-less portion of it in the previous one. Only do
         // this if the line is flush with the content edge of the block, though. If it isn't, it
         // means that the line was pushed downwards by preceding floats that didn't fit beside the
         // line, and we don't want to move all that, since it has already been established that it
         // fits nicely where it is.
         LayoutUnit lineHeight = lineBox.lineBottomWithLeading() - lineBox.lineTopWithLeading();
         LayoutUnit totalLogicalHeight = lineHeight + std::max<LayoutUnit>(0, lineLogicalOffset);
         LayoutUnit pageLogicalHeightAtNewOffset = block.pageLogicalHeightForOffset(lineLogicalOffset + remainingLogicalHeight);
         // It's rather pointless to break before the block if the current line isn't going to
         // fit in the same column or page, so check that as well.
-        if (totalLogicalHeight < pageLogicalHeightAtNewOffset)
+        if (totalLogicalHeight <= pageLogicalHeightAtNewOffset)
             wantsStrutOnBlock = true;
     }
     return wantsStrutOnBlock && block.allowsPaginationStrut();
 }
 
 void LayoutBlockFlow::adjustLinePositionForPagination(RootInlineBox& lineBox, LayoutUnit& delta)
 {
     // TODO(mstensho): Pay attention to line overflow. It should be painted in the same column as
     // the rest of the line, possibly overflowing the column. We currently only allow overflow above
     // the first column. We clip at all other column boundaries, and that's how it has to be for
@@ skipping 2291 matching lines @@
     FrameView* frameView = document().view();
     LayoutUnit top = (style()->position() == FixedPosition) ? 0 : frameView->scrollOffset().height();
     int visibleHeight = frameView->visibleContentRect(IncludeScrollbars).height();
     if (size().height() < visibleHeight)
         top += (visibleHeight - size().height()) / 2;
     setY(top);
     dialog->setCentered(top);
 }
 
 } // namespace blink