Implement main blink target in GN.

Source/bindings/modules/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("//third_party/WebKit/Source/modules/modules.gni")
 import("//third_party/WebKit/Source/bindings/core/core.gni")
 import("//third_party/WebKit/Source/bindings/modules/modules.gni")
 import("//third_party/WebKit/Source/bindings/scripts/scripts.gni")
 import("//third_party/WebKit/Source/build/scripts/scripts.gni")
 
+visibility = "//third_party/WebKit/*"
+
 # GYP version: Source/bindings/modules/generated.gyp:bindings_modules_generated
 group("bindings_modules_generated") {
   deps = [
     ":modules_bindings_generated_event_interfaces",
     ":bindings_modules_generated_event_modules_factory",
     ":bindings_modules_generated_event_modules_names",
     ":bindings_modules_generated_event_target_modules_factory",
     ":bindings_modules_generated_event_target_modules_names",
   ]
 }
@@ skipping 88 matching lines @@
         root_build_dir),
   ]
 
   deps = [
     ":interfaces_info_individual_modules",
     "//third_party/WebKit/Source/bindings/core:interfaces_info_individual_core",
   ]
 }