bindings GYP: split off scripts

Source/bindings/bindings.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': [
         'v8/v8.gypi',
     ],
     'variables': {
-        'bindings_scripts_dir': 'scripts',
         'blink_output_dir': '<(SHARED_INTERMEDIATE_DIR)/blink',
         'bindings_output_dir': '<(SHARED_INTERMEDIATE_DIR)/blink/bindings',
         'bindings_unittest_files': [
             '<@(bindings_v8_unittest_files)',
         ],
         'conditions': [
             # The bindings generator can skip writing generated files if they
             # are identical to the already existing file, which avoids
             # recompilation.  However, a dependency (earlier build step) having
             # a newer timestamp than an output (later build step) confuses some
             # build systems, so only use this on ninja, which explicitly
             # supports this use case (gyp turns all actions into ninja restat
             # rules).
             ['"<(GENERATOR)"=="ninja"', {
               'write_file_only_if_changed': '1',
             }, {
               'write_file_only_if_changed': '0',
             }],
         ],
     },
 }