Reorganize Blink IDL build, delete obsolete GYP files.

third_party/WebKit/Source/bindings/modules/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',
-    ],
-    'variables': {
-        # Note: list duplicated in v8.gni.
-        'bindings_modules_v8_files': [
-            '<@(bindings_modules_v8_custom_files)',
-            'DictionaryHelperForModules.cpp',
-            'ModuleBindingsInitializer.cpp',
-            'ModuleBindingsInitializer.h',
-            'ScriptValueSerializerForModules.cpp',
-            'ScriptValueSerializerForModules.h',
-            'SerializedScriptValueForModulesFactory.cpp',
-            'SerializedScriptValueForModulesFactory.h',
-            'ToV8ForModules.h',
-            'V8BindingForModules.cpp',
-            'V8BindingForModules.h',
-            'V8IDBObserverCallback.cpp',
-            'V8IDBObserverCallback.h',
-            'V8ServiceWorkerMessageEventInternal.h',
-            'WebGLAny.cpp',
-            'WebGLAny.h',
-        ],
-        # Note: list duplicated in v8.gni.
-        'bindings_modules_v8_unittest_files': [
-            'V8BindingForModulesTest.cpp',
-        ],
-    },
-}