The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4c7bc246716d75389c0896744a72bdb586f6ca60

commit 4c7bc246716d75389c0896744a72bdb586f6ca60
Author: Kyoko Muto <kymuto@google.com>
Date: Fri Aug 03 06:51:28 2018

Merge FlatTreeTraversal and FlatTreeTraversalNG

BUG=  867331 

Change-Id: I886542193ed17743d8e10c11ae9c2c5036c8187b
Reviewed-on: https://chromium-review.googlesource.com/1159937
Commit-Queue: Kyoko Muto <kymuto@google.com>
Reviewed-by: Hayato Ito <hayato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580464}
[modify] https://crrev.com/4c7bc246716d75389c0896744a72bdb586f6ca60/third_party/blink/renderer/core/BUILD.gn
[modify] https://crrev.com/4c7bc246716d75389c0896744a72bdb586f6ca60/third_party/blink/renderer/core/dom/BUILD.gn
[modify] https://crrev.com/4c7bc246716d75389c0896744a72bdb586f6ca60/third_party/blink/renderer/core/dom/flat_tree_traversal.cc
[modify] https://crrev.com/4c7bc246716d75389c0896744a72bdb586f6ca60/third_party/blink/renderer/core/dom/flat_tree_traversal.h
[delete] https://crrev.com/37427655b287f2264e0d3784fe7a486b1e4f3148/third_party/blink/renderer/core/dom/flat_tree_traversal_ng.cc
[delete] https://crrev.com/37427655b287f2264e0d3784fe7a486b1e4f3148/third_party/blink/renderer/core/dom/flat_tree_traversal_ng.h
[delete] https://crrev.com/37427655b287f2264e0d3784fe7a486b1e4f3148/third_party/blink/renderer/core/dom/flat_tree_traversal_ng_test.cc
[modify] https://crrev.com/4c7bc246716d75389c0896744a72bdb586f6ca60/third_party/blink/renderer/core/dom/flat_tree_traversal_test.cc