Make chrome/common compile in GN

build/json_schema_compile.gypi

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     # When including this gypi, the following variables must be set:
     #   schema_files: a list of json or IDL files that comprise the api model.
     #   cc_dir: path to generated files
     #   root_namespace: the C++ namespace that all generated files go under
     # Functions and namespaces can be excluded by setting "nocompile" to true.
     # The default root path of API implementation sources is
     # chrome/browser/extensions/api and can be overridden by setting "impl_dir".
     'api_gen_dir': '<(DEPTH)/tools/json_schema_compiler',
     'api_gen': '<(api_gen_dir)/compiler.py',
     'impl_dir%': 'chrome/browser/extensions/api',
   },
   'rules': [
     {
+      # GN version: //build/json_schema.gni
+      #             (json_schema_compile template)
       'rule_name': 'genapi',
       'msvs_external_rule': 1,
       'extension': 'json',
       'inputs': [
         '<(api_gen_dir)/cc_generator.py',
         '<(api_gen_dir)/code.py',
         '<(api_gen_dir)/compiler.py',
         '<(api_gen_dir)/cpp_generator.py',
         '<(api_gen_dir)/cpp_type_generator.py',
         '<(api_gen_dir)/cpp_util.py',
@@ skipping 74 matching lines @@
   ],
   'direct_dependent_settings': {
     'include_dirs': [
       '<(SHARED_INTERMEDIATE_DIR)',
     ]
   },
   # This target exports a hard dependency because it generates header
   # files.
   'hard_dependency': 1,
 }