Update from https://crrev.com/304121

third_party/zlib/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.
 
 config("zlib_config") {
   include_dirs = [ "." ]
 }
 
 static_library("zlib_x86_simd") {
   if (!is_win && (cpu_arch == "x86" || cpu_arch == "x64")) {
     sources = [ "crc_folding.c", "fill_window_sse.c" ]
     cflags = [ "-msse2", "-msse4.2", "-mpclmul" ]
   } else {
     sources = [ "simd_stub.c"]
-  }
-  if (is_win) {
-    cflags = [ "/wd4324" ]
+    if (is_win) {
+      # TODO(GYP): crbug.com/431462 disable warning about structure padding.
+      cflags = [ "/wd4324" ]
+    }
   }
 }
 
 static_library("zlib") {
   if (!is_win) {
     # Don't stomp on "libzlib" on other platforms.
     output_name = "chrome_zlib"
   }
 
   sources = [
@@ skipping 81 matching lines @@
     "google/zip_internal.cc",
     "google/zip_internal.h",
     "google/zip_reader.cc",
     "google/zip_reader.h",
   ]
   deps = [
     ":minizip",
     "//base",
   ]
 }