Update Chomium's build files to work w/ latest GN binaries.

ppapi/shared_impl/BUILD.gn

 # Copyright 2015 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.
 
 component("shared_impl") {
   output_name = "ppapi_shared"
 
   sources = [
     "array_var.cc",
     "array_var.h",
@@ skipping 125 matching lines @@
       "ppb_video_decoder_shared.h",
       "private/ppb_char_set_shared.cc",
       "private/ppb_char_set_shared.h",
     ]
   }
 
   # TODO(GYP) this isn't correct. This should only be specifically for the
   # nacl_win64 build (cross-compiled for a 32-bit Chrome), rather than the
   # native 64-bit Chrome build.
   # See also //ppapi/thunk
-  if (is_win && cpu_arch == "x64" && current_toolchain != default_toolchain) {
+  if (is_win && current_cpu == "x64" && current_toolchain != default_toolchain) {
     sources -= [
       "ppb_audio_shared.cc",
       "ppb_graphics_3d_shared.cc",
       "ppb_opengles2_shared.cc",
       "private/net_address_private_impl.cc",
       "private/ppb_host_resolver_shared.cc",
     ]
   }
 
   defines = [
@@ skipping 49 matching lines @@
   deps = [
     "//base/test:test_support",
     "//ipc",
     "//ipc:test_support",
     "//ppapi/proxy",
     "//ppapi/shared_impl",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }