Split bindings/v8/custom into core and modules.

Source/bindings/v8/v8.gypi

 # 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.
 
 {
     'includes': [
-        'custom/custom.gypi',
+        # FIXME: should move bindings_v8_files to bindings/core/v8 or
+        # bindings/modules/v8.
+        '../core/v8/custom/custom.gypi',
+        '../modules/v8/generated.gypi',
     ],
     'variables': {
         'bindings_v8_dir': '.',
         'bindings_v8_files': [
-            '<@(bindings_v8_custom_files)',
+            '<@(bindings_core_v8_custom_files)',
             'ActiveDOMCallback.cpp',
             'ActiveDOMCallback.h',
             'ArrayValue.cpp',
             'ArrayValue.h',
             'BindingSecurity.cpp',
             'BindingSecurity.h',
             'CallbackPromiseAdapter.h',
             'CustomElementBinding.cpp',
             'CustomElementBinding.h',
             'CustomElementConstructorBuilder.cpp',
@@ skipping 128 matching lines @@
             'npruntime.cpp',
             'npruntime_impl.h',
             'npruntime_priv.h',
         ],
         'bindings_v8_unittest_files': [
             'IDBBindingUtilitiesTest.cpp',
             'ScriptPromiseTest.cpp',
         ],
     },
 }