Remove third_party/libjingle and update GN targets.

remoting/signaling/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.
 
 static_library("signaling") {
   sources = [
     "delegating_signal_strategy.cc",
     "delegating_signal_strategy.h",
     "iq_sender.cc",
     "iq_sender.h",
@@ skipping 16 matching lines @@
     "xmpp_stream_parser.h",
   ]
 
   configs += [
     "//build/config/compiler:no_size_t_to_int_warning",
     "//build/config/compiler:wexit_time_destructors",
   ]
 
   public_deps = [
     "//remoting/proto",
-    "//third_party/libjingle",
     "//third_party/libjingle_xmpp",
+    "//third_party/webrtc_overrides",
   ]
 
   deps = [
     "//base",
     "//crypto",
     "//jingle:jingle_glue",
     "//net",
     "//remoting/base",
   ]
 
@@ skipping 36 matching lines @@
     "xmpp_signal_strategy_unittest.cc",
     "xmpp_stream_parser_unittest.cc",
   ]
 
   deps = [
     ":test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }