Remove -fstack-protector-strong from the ChromeOS GN build.

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/linux/sysroot.gni")
 
 # Base compiler configuration.
 config("compiler") {
   include_dirs = [ "//", root_gen_dir ]
   if (is_win) {
@@ skipping 14 matching lines @@
     ]
     cflags_cc = [
       "-fno-exceptions",
       "-fno-threadsafe-statics",
       "-fvisibility-inlines-hidden",
     ]
     ldflags = [
     ]
 
     # Stack protection.
-    # TODO(brettw) why do we have different values for all of these cases?
     if (is_mac) {
       cflags += "-fstack-protector-all"
-    } else if (is_chromeos) {
-      cflags += "-fstack-protector-strong"
     } else if (is_linux) {
       cflags += [ "-fstack-protector", "--param=ssp-buffer-size=4" ]
     }
 
     if (is_mac) {
       # Mac-specific compiler flags setup.
       # ----------------------------------
 
       # These flags are shared between the C compiler and linker.
       common_mac_flags = [
@@ skipping 365 matching lines @@
   } else {
     cflags = [ "-g1" ]
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }