The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a4d523a0de35631166275a4126523e3a13e170e3

commit a4d523a0de35631166275a4126523e3a13e170e3
Author: Rune Lillesveen <rune@opera.com>
Date: Thu Aug 17 18:48:58 2017

Check for HasNormalColumnGap() for LayoutView style changes.

PropagateStyleToViewport() propagated the absolute length of column-gap
only, and did not consider the "normal" keyword value. A change between
0 and "normal" was not detected as a change, hence the pages were not
laid out with the new value.

Bug:  756423 
Change-Id: Idfe6c34b2e88fb741f25950c6d5a79290e33b728
Reviewed-on: https://chromium-review.googlesource.com/618926
Commit-Queue: Rune Lillesveen <rune@opera.com>
Reviewed-by: Morten Stenshorne <mstensho@opera.com>
Cr-Commit-Position: refs/heads/master@{#495256}
[modify] https://crrev.com/a4d523a0de35631166275a4126523e3a13e170e3/third_party/WebKit/LayoutTests/compositing/columns/composited-in-paginated.html
[add] https://crrev.com/a4d523a0de35631166275a4126523e3a13e170e3/third_party/WebKit/LayoutTests/fast/pagination/paged-x-column-gap.html
[modify] https://crrev.com/a4d523a0de35631166275a4126523e3a13e170e3/third_party/WebKit/LayoutTests/fast/pagination/paged-x-to-paged-y.html
[modify] https://crrev.com/a4d523a0de35631166275a4126523e3a13e170e3/third_party/WebKit/LayoutTests/fast/pagination/paged-y-to-paged-x.html
[modify] https://crrev.com/a4d523a0de35631166275a4126523e3a13e170e3/third_party/WebKit/Source/core/dom/Document.cpp