Revert "Roll HarfBuzz to 1.8.2 plus build fix"

This reverts commit ce5f0c23.

Reason for revert: presumably caused crashes on internal tests
(see https://crbug.com/860250 and https://crbug.com/860268 for
builder links).

Original change's description:
> Roll HarfBuzz to 1.8.2 plus build fix
> 
> https://chromium.googlesource.com/external/github.com/harfbuzz/harfbuzz/+log/957e7756634..2cb075fe26
> 
> Contains a fix for Khmer shaping.
> 
> Bug: 847034
> Change-Id: I0ac1fdf4df69e5c5dd3cc8a877809db99ce40fda
> Reviewed-on: https://chromium-review.googlesource.com/1123826
> Reviewed-by: Ben Wagner <bungeman@chromium.org>
> Commit-Queue: Dominik Röttsches <drott@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#572188}

TBR=bungeman@chromium.org,kojii@chromium.org,drott@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 847034, 860250, 860268
Change-Id: Icd36bffb962ca04e99eda0c56779ce1a21b4ce26
Reviewed-on: https://chromium-review.googlesource.com/1126339Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572603}

DEPS

@@ -161,7 +161,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling HarfBuzz
   # and whatever else without interference from each other.
-  'harfbuzz_revision': '2cb075fe26201f3e370fccfff6c1bc242b5acc79',
+  'harfbuzz_revision': '957e7756634a4fdf1654041e20e883cf964ecac9',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling catapult
   # and whatever else without interference from each other.

third_party/harfbuzz-ng/BUILD.gn

@@ -46,7 +46,6 @@ if (use_system_harfbuzz) {
 
     sources = [
       "src/src/hb-atomic-private.hh",
-      "src/src/hb-blob-private.hh",
       "src/src/hb-blob.cc",
       "src/src/hb-blob.h",
       "src/src/hb-buffer-deserialize-json.hh",
@@ -158,7 +157,6 @@ if (use_system_harfbuzz) {
       "src/src/hb-shaper-list.hh",
       "src/src/hb-shaper-private.hh",
       "src/src/hb-shaper.cc",
-      "src/src/hb-static.cc",
       "src/src/hb-string-array.hh",
       "src/src/hb-subset-glyf.hh",
       "src/src/hb-subset-plan.h",
@@ -178,7 +176,6 @@ if (use_system_harfbuzz) {
       "HAVE_ICU",
       "HAVE_ICU_BUILTIN",
       "HAVE_INTEL_ATOMIC_PRIMITIVES",
-      "HB_NO_MMAP",
     ]
 
     if (is_component_build) {

third_party/harfbuzz-ng/README.chromium

 Name: harfbuzz-ng
 Short Name: harfbuzz-ng
 URL: http://harfbuzz.org
-Version: 1.8.2
-Date: 20180703
-Revision: 2cb075fe26201f3e370fccfff6c1bc242b5acc79
+Version: 1.7.6
+Date: 20180319
+Revision: 957e7756634a4fdf1654041e20e883cf964ecac9
 Security Critical: yes
 License: MIT
 License File: src/COPYING
@@ -31,26 +31,16 @@ Currently we are intentionally not building the following files from HarfBuzz.
     dump-khmer-data.cc
     dump-myanmar-data.cc
     dump-use-data.cc
-    hb-aat-fmtx-table.hh
-    hb-aat-gcid-table.hh
     hb-aat-layout-ankr-table.hh
-    hb-aat-layout-bsln-table.hh
     hb-aat-layout-common-private.hh
-    hb-aat-layout-feat-table.hh
     hb-aat-layout-kerx-table.hh
     hb-aat-layout-morx-table.hh
     hb-aat-layout-private.hh
     hb-aat-layout-trak-table.hh
     hb-aat-layout.cc
-    hb-aat-ltag-table.hh
     hb-directwrite.cc
     hb-directwrite.h
     hb-fallback-shape.cc
-    hb-map-private.hh
-    hb-map.cc
-    hb-map.h
-    hb-ot-color-sbix-table.hh
-    hb-ot-color-svg-table.hh
     hb-ot-color.cc
     hb-subset-glyf.cc
     hb-subset-input.cc