Reorganize Blink IDL build, delete obsolete GYP files.

third_party/WebKit/Source/bindings/modules/v8/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/bindings/modules/v8/generated.gni")
 import("//third_party/WebKit/Source/bindings/scripts/scripts.gni")
 import("//third_party/WebKit/Source/modules/modules.gni")
+import("//third_party/WebKit/Source/modules/modules_idl_files.gni")
 
 visibility = [ "//third_party/WebKit/*" ]
 
 # bindings_modules_generated in modules/v8/generated.gyp
 group("bindings_modules_generated") {
   public_deps = [
     ":bindings_modules_impl_generated",
     ":bindings_modules_v8_generated_aggregate",
     ":bindings_modules_v8_generated_individual",
     ":bindings_modules_v8_generated_init_partial",
@@ skipping 70 matching lines @@
     "--output",
     rebase_path(bindings_modules_generated_init_partial_interfaces_file,
                 root_build_dir),
     "--write-file-only-if-changed=1",
   ]
 
   deps = [
     "//third_party/WebKit/Source/bindings/modules:interfaces_info",
   ]
 }