Get `gn gen` to succeed on Windows

net/BUILD.gn

 # Copyright (c) 2013 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("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//url/config.gni")
 
 # TODO(cjhopman): //build/config/android/rules.gni also imports grit_rule.gni.
@@ skipping 271 matching lines @@
       "ssl/openssl_ssl_util.cc",
       "ssl/openssl_ssl_util.h",
     ]
     if (is_mac) {
       sources -= [
         "ssl/openssl_platform_key_mac.cc",
       ]
     }
     if (is_win) {
       sources -= [
-        "cert/cert/sha256_legacy_support_openssl_win.cc",
         "ssl/openssl_platform_key_win.cc",
       ]
     }
   }
 
   if (!use_openssl_certs) {
     sources -= [
       "base/keygen_handler_openssl.cc",
       "base/openssl_private_key_store.h",
       "base/openssl_private_key_store_memory.cc",
@@ skipping 1083 matching lines @@
   sources = [ "quic/quic_server_bin.cc" ]
   deps = [
     ":quic_tools",
     ":net",
     "//base",
     "//third_party/boringssl",
   ]
 }
 
 }  # !is_android