Gtk3 ui: Add libgtk3ui as a separate build component

third_party/harfbuzz-ng/BUILD.gn

 # Copyright 2014 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/chrome_build.gni")
 import("//build/config/features.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//build/config/ui.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
@@ skipping 30 matching lines @@
         # by static_assert).
         "-Wno-unused-local-typedef",
       ]
     }
     if (is_win) {
       # Result of 32-bit shift implicitly converted to 64 bits.
       cflags += [ "/wd4334" ]
     }
   }
 
-  # See also chrome/browser/ui/libgtk2ui/BUILD.gn which pulls this.
+  # See also chrome/browser/ui/libgtkui/BUILD.gn which pulls this.
   config("pangoft2_link_hack") {
     if (is_linux && use_pango && !is_chromeos && !is_official_build &&
         current_cpu != "arm" && current_cpu != "mipsel" && !is_component_build) {
       # These symbols are referenced from libpangoft2, which will be
       # dynamically linked later.
       ldflags = [ "-Wl,-uhb_ft_face_create_cached,-uhb_glib_get_unicode_funcs" ]
     }
   }
 
   static_library("harfbuzz-ng") {
@@ skipping 154 matching lines @@
 fuzzer_test("harfbuzz_fuzzer") {
   sources = [
     "fuzz/harfbuzz_fuzzer.cc",
   ]
   deps = [
     ":harfbuzz-ng",
   ]
   libfuzzer_options = [ "max_len=16800" ]
   seed_corpus = "fuzz/seed_corpus"
 }