Add local suppresion for -Wparentheses and enable everywhere on Windows.

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")
 import("//build/config/chrome_build.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
@@ skipping 797 matching lines @@
       "-Wno-incompatible-pointer-types",  # http://crbug.com/504696
       "-Wno-int-to-void-pointer-cast",  # http://crbug.com/504697
       "-Wno-invalid-noreturn",  # http://crbug.com/504698
       "-Wno-logical-op-parentheses",  # http://crbug.com/504699
       "-Wno-microsoft",  # http://crbug.com/505296
       "-Wno-missing-braces",  # http://crbug.com/505297
       "-Wno-missing-declarations",  # http://crbug.com/505298
       "-Wno-msvc-include",  # http://crbug.com/505299
       "-Wno-null-dereference",  # http://crbug.com/
       "-Wno-overloaded-virtual",  # http://crbug.com/505301
-      "-Wno-parentheses",  # http://crbug.com/505302
       "-Wno-pointer-sign",  # http://crbug.com/505303
       "-Wno-reorder",  # http://crbug.com/505304
       "-Wno-return-type-c-linkage",  # http://crbug.com/505305
       "-Wno-self-assign",  # http://crbug.com/505306
       "-Wno-sometimes-uninitialized",  # http://crbug.com/505307
       "-Wno-switch",  # http://crbug.com/505308
       "-Wno-tautological-compare",  # http://crbug.com/505309
       "-Wno-unknown-pragmas",  # http://crbug.com/505314
       "-Wno-unsequenced",  # http://crbug.com/505315
       "-Wno-unused-function",  # http://crbug.com/505316
@@ skipping 417 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }