gn win: Always warnings as errors

build/config/compiler/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/android/config.gni")
 if (cpu_arch == "arm") {
   import("//build/config/arm.gni")
 }
 if (is_posix) {
   import("//build/config/gcc/gcc_version.gni")
@@ skipping 433 matching lines @@
     ]
 
   }
 }
 
 # chromium_code ---------------------------------------------------------------
 #
 # Toggles between higher and lower warnings for code that is (or isn't)
 # part of Chromium.
 
-# TODO: -Werror and /WX should always be on, independent of chromium_code
+# TODO: -Werror should always be on, independent of chromium_code
 # http://crbug.com/393046
 config("chromium_code") {
   if (is_win) {
     cflags = [
       "/W4",  # Warning level 4.
-      "/WX",  # Treat warnings as errors.
     ]
   } else {
     cflags = [
       "-Wall",
 
       # GCC turns on -Wsign-compare for C++ under -Wall, but clang doesn't,
       # so we specify it explicitly.
       # TODO(fischman): remove this if http://llvm.org/PR10448 obsoletes it.
       # http://code.google.com/p/chromium/issues/detail?id=90453
       "-Wsign-compare",
@@ skipping 88 matching lines @@
 
 # Warnings ---------------------------------------------------------------------
 #
 # This is where we disable various warnings that we've decided aren't
 # worthwhile, and enable special warnings.
 
 config("default_warnings") {
   if (is_win) {
     # Please keep ordered and add names if you add more.
     cflags = [
+      "/WX",      # Treat warnings as errors.
       "/wd4018",  # Comparing signed and unsigned values.
       "/wd4100",  # Unreferenced formal function parameter.
       "/wd4121",  # Alignment of a member was sensitive to packing.
       "/wd4125",  # Decimal digit terminates octal escape sequence.
       "/wd4127",  # Conditional expression is constant.
       "/wd4130",  # Logical operation on address of string constant.
       "/wd4189",  # A variable was declared and initialized but never used.
       "/wd4201",  # Nonstandard extension used: nameless struct/union.
       "/wd4238",  # Nonstandard extension used: class rvalue used as lvalue.
       "/wd4244",  # Conversion: possible loss of data.
@@ skipping 267 matching lines @@
   } else {
     cflags = [ "-g1" ]
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }