Fix some TODO(GYP) in the GN build.

third_party/libjingle/BUILD.gn

 # Copyright 2014 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/features.gni")
 
 # From third_party/libjingle/libjingle.gyp's target_defaults.
 config("jingle_unexported_configs") {
   defines = [
     "EXPAT_RELATIVE_PATH",
@@ skipping 36 matching lines @@
   ]
   defines = [
     "FEATURE_ENABLE_SSL",
     "FEATURE_ENABLE_VOICEMAIL",
     "EXPAT_RELATIVE_PATH",
     "GTEST_RELATIVE_PATH",
     "NO_MAIN_THREAD_WRAPPING",
     "NO_SOUND_SYSTEM",
   ]
 
-  # TODO(GYP): Port is_win blocks.

[brettw, 2016/05/23 22:06:26]

The only missing Windows block disables some warnings. Since we don't see those
warnings, the disabling no longer seems to be necessary.

   if (is_linux) {
     defines += [
       "LINUX",
       "WEBRTC_LINUX",
     ]
   }
   if (is_mac) {
     defines += [
       "OSX",
       "WEBRTC_MAC",
     ]
   }
   if (is_ios) {
     defines += [
       "IOS",
       "WEBRTC_MAC",
       "WEBRTC_IOS",
     ]
   }
   if (is_win) {
     defines += [ "WEBRTC_WIN" ]
   }
   if (is_android) {
     defines += [ "ANDROID" ]
   }
   if (is_posix) {
     defines += [ "WEBRTC_POSIX" ]
   }
-
-  # TODO(GYP): Support these in GN.
-  # if (is_bsd) {
-  #   defines += [ "BSD" ]
-  # }
-  # if (is_openbsd) {
-  #   defines += [ "OPENBSD" ]
-  # }
-  # if (is_freebsd) {
-  #   defines += [ "FREEBSD" ]
-  # }
   if (is_chromeos) {
     defines += [ "CHROMEOS" ]
   }
 }
 
 # From third_party/libjingle/libjingle.gyp's target_defaults.
 group("jingle_deps") {
   public_deps = [
     "//third_party/expat",
   ]
@@ skipping 322 matching lines @@
     sources = [
       "$p2p_dir/stunprober/stunprober.cc",
     ]
 
     deps = [
       ":libjingle_webrtc_common",
       "//third_party/webrtc/base:rtc_base",
     ]
   }
 }  # enable_webrtc
-# TODO(GYP): Port libjingle.gyp's enable_webrtc condition block.

[brettw, 2016/05/23 22:06:26]

This is the block above.