The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7ac60e68734131f92bc9c7839612b59091e46be7

commit 7ac60e68734131f92bc9c7839612b59091e46be7
Author: Dominik Röttsches <drott@chromium.org>
Date: Wed Mar 07 16:39:30 2018

Roll HarfBuzz to 1.7.6

Taking on important fixes to hb_set_union/subtract/difference.

Bug:  819624 
Change-Id: I41088581a41565cbbd99a430425e2ab9be6ee939
Reviewed-on: https://chromium-review.googlesource.com/951736
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541462}
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/BUILD.gn
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/NEWS
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/README.chromium
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-buffer-deserialize-json.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-buffer-deserialize-text.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-gobject-structs.h
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-open-file-private.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-open-type-private.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-cmap-table.hh
[rename] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-color-cbdt-table.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-color-colr-table.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-color-cpal-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-font.cc
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-glyf-table.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-hdmx-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-head-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-hmtx-table.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout-base-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout-common-private.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout-gdef-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout-gpos-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout-gsub-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout-private.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout.cc
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-layout.h
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-maxp-table.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-os2-table.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-os2-unicode-ranges.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-ot-shape.cc
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-set-private.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-subset-glyf.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-subset-plan.hh
[add] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-subset-private.hh
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-subset.h
[modify] https://crrev.com/7ac60e68734131f92bc9c7839612b59091e46be7/third_party/harfbuzz-ng/src/hb-version.h