Remove some rtc hacks 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/crypto.gni")
 import("//build/config/features.gni")
 
 # From third_party/libjingle/libjingle.gyp's target_defaults.
 config("jingle_unexported_configs") {
   defines = [
@@ skipping 498 matching lines @@
     configs += [ ":jingle_unexported_configs" ]
     direct_dependent_configs = [ ":jingle_direct_dependent_configs" ]
 
     deps = [
       "//third_party/libsrtp",
       "//third_party/webrtc/modules/media_file",
       "//third_party/webrtc/modules/video_capture",
       "//third_party/webrtc/modules/video_render",
     ]
 
-    # TODO(GYP) this should be removed and we should get this config by one of
-    # the webrtc targets specifying it for the direct_dependent_configs.
-    #configs += [ "//third_party/webrtc:common_config" ]  # TODO(GYP)
-
     if (!is_ios) {
       # TODO(mallinath) - Enable SCTP for iOS.
       sources += [
         "source/talk/media/sctp/sctpdataengine.cc",
         "source/talk/media/sctp/sctpdataengine.h",
       ]
       defines = [ "HAVE_SCTP" ]
       deps += [ "//third_party/usrsctp" ]
     }
 
@@ skipping 23 matching lines @@
       ":libjingle_webrtc_common",
       "//third_party/webrtc",
       "//third_party/webrtc/system_wrappers",
       "//third_party/webrtc/voice_engine",
     ]
   }
 
 }  # enable_webrtc
 
 # TODO(GYP): Port libjingle.gyp's enable_webrtc condition block.