Add remaining remoting targets for the GN build.

remoting/host/it2me/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")
+import("//remoting/remoting_host.gni")
 import("//remoting/remoting_srcs.gni")
 
 source_set("common") {
   sources = rebase_path(
           remoting_host_srcs_gypi_values.remoting_it2me_host_static_sources,
           ".",
           "//remoting")
 
   configs += [
     "//build/config/compiler:wexit_time_destructors",
     "//remoting:version",
   ]
 
   deps = [
     "//base:i18n",
     "//net:net",
     "//remoting/base",
     "//remoting/host",
     "//remoting/protocol",
     "//remoting/resources",
   ]
 }
+
+if (!is_win && enable_remoting_host) {
+  executable("remote_assistance_host") {
+    sources = [
+      "it2me_native_messaging_host_entry_point.cc",
+      "it2me_native_messaging_host_main.cc",
+      "it2me_native_messaging_host_main.h",
+    ]
+
+    configs += [
+      "//build/config/compiler:wexit_time_destructors",
+      "//remoting:version",
+    ]
+
+    deps = [
+      ":common",
+      "//remoting/host",
+      "//remoting/host/native_messaging",
+      "//remoting/proto",
+    ]
+
+    if (enable_webrtc) {
+      deps += [ "//third_party/libjingle:libjingle_webrtc" ]
+    }
+
+    if (is_linux) {
+      deps += [ "//build/config/linux/gtk" ]
+    }
+  }
+}