Add lots of testonly annotations to the GN build.

jingle/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")
 
 if (enable_webrtc || !is_android) {
   jingle_includes = exec_script("//build/gypi_to_gn.py",
                                 [ rebase_path("jingle.gypi") ],
                                 "scope",
@@ skipping 90 matching lines @@
     deps = [
       ":notifier",
       "//base",
       "//testing/gmock",
     ]
   }
 
   # GYP version: jingle/jingle.gyp:jingle_unittests
   # TODO(GYP): Convert to executable when its dependencies are linkable.
   source_set("jingle_unittests") {
+    testonly = true
     sources = [
       "glue/channel_socket_adapter_unittest.cc",
       "glue/chrome_async_socket_unittest.cc",
       "glue/fake_ssl_client_socket_unittest.cc",
       "glue/jingle_glue_mock_objects.cc",
       "glue/jingle_glue_mock_objects.h",
       "glue/logging_unittest.cc",
       "glue/mock_task.cc",
       "glue/mock_task.h",
       "glue/proxy_resolving_client_socket_unittest.cc",
@@ skipping 58 matching lines @@
       "notifier/base/notifier_options.h",
     ]
     deps = [
       "//base",
       "//net"
     ]
   }
 
   source_set("notifier_test_util") { }
 }