Remove unused V8 integration code in Sky

sky/engine/bindings/core/idl.gni

-# 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("//sky/engine/bindings/idl.gni")
-import("//sky/engine/core/core.gni")
-
-# IDL file lists; see: http://www.chromium.org/developers/web-idl-interfaces
-# Interface IDL files: generate individual bindings (includes testing)
-core_interface_idl_files = core_idl_files
-
-# Static IDL files
-core_static_interface_idl_files = core_idl_files
-
-core_static_dependency_idl_files = core_dependency_idl_files
-
-# Generated IDL files
-core_generated_dependency_idl_files =
-    # FIXME: Generate separate core_global_constructors_idls
-    # http://crbug.com/358074
-    generated_global_constructors_idl_files  # partial interfaces
-
-# Static IDL files / Generated IDL files
-#
-# In GYP, paths need to be passed separately for static and generated files, as
-# static files are listed in a temporary file (b/c too long for command line),
-# but generated files must be passed at the command line, as their paths are
-# not fixed at GYP time, when the temporary file is generated, because their
-# paths depend on the build directory, which varies.
-#
-# FIXME: GN does not have this restriction and we can combine them. While GYP
-# is still supported, we match its behavior for easier maintenance but this can
-# be simplified.
-core_static_idl_files =
-    core_static_interface_idl_files + core_static_dependency_idl_files
-core_generated_idl_files = core_generated_dependency_idl_files
-
-# Dependency IDL files: don't generate individual bindings, but do process
-# in IDL dependency computation, and count as build dependencies
-# 'core_dependency_idl_files' is already used in engine/core, so avoid
-# collision
-core_all_dependency_idl_files =
-    core_static_dependency_idl_files + core_generated_dependency_idl_files