Convert make_names and make_event_factory to use json5 config format.

third_party/WebKit/Source/platform/loader/BUILD.gn

 # Copyright 2017 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/build/scripts/scripts.gni")
 import("//third_party/WebKit/Source/platform/platform_generated.gni")
 
 make_names("make_platform_loader_generated_fetch_initiator_type_names") {
-  in_files = [ "fetch/FetchInitiatorTypeNames.in" ]
+  in_files = [ "fetch/FetchInitiatorTypeNames.json5" ]
   outputs = [
     "$blink_platform_output_dir/loader/fetch/FetchInitiatorTypeNames.cpp",
     "$blink_platform_output_dir/loader/fetch/FetchInitiatorTypeNames.h",
   ]
 }
 
 source_set("loader") {
   # This target is a logical part of the platform and only the platform target
   # should depend on it.
   visibility = [ "//third_party/WebKit/Source/platform" ]
@@ skipping 54 matching lines @@
     ":make_platform_loader_generated_fetch_initiator_type_names",
   ]
 
   public_deps = [
     "//base",
     "//skia",
     "//third_party/icu",
     "//v8",
   ]
 }