Add remoting::protocol::NetworkStateObserver interface.

remoting/protocol/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")
 
 static_library("protocol") {
   sources = [
     "audio_decode_scheduler.cc",
     "audio_decode_scheduler.h",
@@ skipping 147 matching lines @@
     "third_party_host_authenticator.h",
     "token_validator.h",
     "transport.cc",
     "transport.h",
     "transport_context.cc",
     "transport_context.h",
     "v2_authenticator.cc",
     "v2_authenticator.h",
     "validating_authenticator.cc",
     "validating_authenticator.h",
+    "video_channel_state_observer.h",
     "video_renderer.h",
     "video_stats_stub.h",
     "video_stub.h",
   ]
 
   configs += [
     "//build/config:precompiled_headers",
     "//build/config/compiler:no_size_t_to_int_warning",
     "//build/config/compiler:wexit_time_destructors",
   ]
@@ skipping 148 matching lines @@
     "webrtc_transport_unittest.cc",
   ]
 
   deps = [
     ":test_support",
     "//net:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }