Implement main blink target in GN.

Source/web/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/ui.gni")
 import("//third_party/WebKit/Source/config.gni")
 import("//third_party/WebKit/Source/build/make_file_arrays.gni")
 
+visibility = "//third_party/WebKit/*"
+
 web_gypi = exec_script(
     "//build/gypi_to_gn.py",
     [ rebase_path("web.gypi") ],
     "scope",
     [ "web.gypi" ])
 
 component("web") {
   output_name = "blink_web"
 
   deps = [
@@ skipping 43 matching lines @@
 make_file_arrays("calendar_picker") {
   resources = [
     "resources/calendarPicker.css",
     "resources/calendarPicker.js",
     "resources/pickerButton.css",
     "resources/suggestionPicker.css",
     "resources/suggestionPicker.js",
   ]
   filename = "CalendarPicker"
 }