Build FreeType with HarfBuzz support

build/config/freetype/BUILD.gn

 # Copyright 2017 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
+import("//build/config/freetype/freetype.gni")
+import("//build/config/ui.gni")
+import("//third_party/harfbuzz-ng/harfbuzz.gni")
 
-declare_args() {
-  # Blink needs a recent and properly build-configured FreeType version to
-  # support OpenType variations, color emoji and avoid security bugs. By default
-  # we ship and link such a version as part of Chrome. For distributions that
-  # prefer to keep linking to the version the system, FreeType must be newer
-  # than version 2.7.1 and have color bitmap support compiled in. WARNING:
-  # System FreeType configurations other than as described WILL INTRODUCE TEXT
-  # RENDERING AND SECURITY REGRESSIONS.
-  use_system_freetype = false
-}
-
-group("freetype") {
+# Only to be used as an intermediate target to resolve the cyclic dependency
+# between FreeType and Harfbuzz in HarfBuzz' BUILD.gn
+group("freetype-without-harfbuzz") {
   if (use_system_freetype) {
     public_configs = [ "//build/linux:freetype_from_pkgconfig" ]
   } else {
     public_deps = [
       "//third_party/freetype",
     ]
   }
 }
+
+# Maybe switch name and reduce diff-size by calling the previous target
+# something like freetype2-intermediate or so, and this one - as before -
+# freetype2.
+group("freetype") {
+  if (use_system_freetype) {
+    public_configs = [ "//build/linux:freetype_from_pkgconfig" ]
+  } else {
+    public_deps = [
+      # HarfBuzz dependency needed in order for FreeType autohinting to detect
+      # ligatures and other OpenType mappings.
+      ":freetype-without-harfbuzz",
+      "//third_party/harfbuzz-ng:harfbuzz-ng",
+      "//third_party/harfbuzz-ng:harfbuzz-ng-ft",
+    ]
+  }
+}