build: Fix optimize_for_size build on Linux by adding an is_nacl guard.

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")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 1431 matching lines @@
         # Probably anything that this would catch that wouldn't be caught in a
         # normal build isn't going to actually be a bug, so the incremental
         # value of C4702 for PGO builds is likely very small.
         "/wd4702",
       ]
     }
 
     # Favor size over speed, /O1 must be before the common flags. The GYP
     # build also specifies /Os and /GF but these are implied by /O1.
     cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
-  } else if (optimize_for_size) {
+  } else if (optimize_for_size && !is_nacl) {
     # Favor size over speed.
+    # TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
+    # guard above.
     cflags = [ "-Os" ] + common_optimize_on_cflags
   } else {
     cflags = [ "-O2" ] + common_optimize_on_cflags
   }
   ldflags = common_optimize_on_ldflags
 }
 
 # Same config as 'optimize' but without the WPO flag.
 config("optimize_no_wpo") {
   if (is_win) {
     # Favor size over speed, /O1 must be before the common flags. The GYP
     # build also specifies /Os and /GF but these are implied by /O1.
     cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
-  } else if (optimize_for_size) {
+  } else if (optimize_for_size && !is_nacl) {
     # Favor size over speed.
+    # TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
+    # guard above.
     cflags = [ "-Os" ] + common_optimize_on_cflags
   } else if (optimize_for_fuzzing) {
     cflags = [ "-O1" ] + common_optimize_on_cflags
   } else {
     cflags = [ "-O2" ] + common_optimize_on_cflags
   }
   ldflags = common_optimize_on_ldflags
 }
 
 # Turn off optimizations.
@@ skipping 269 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }