Add tracing service and make the shell+sky_viewer+services talk to it

mojo/shell/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/ui.gni")
 import("//mojo/public/mojo.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 # We don't support building in the component build since mojo apps are
 # inherently components.
@@ skipping 105 matching lines @@
   deps = [
     ":app_child_process_bindings",
     ":external_application_registrar_bindings",
     ":in_process_dynamic_service_runner",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//base:base_static",
     "//mojo/application",
     "//mojo/application_manager",
     "//mojo/common",
+    "//mojo/common:tracing_impl",
     "//mojo/edk/system",
     "//mojo/public/cpp/bindings",
     "//mojo/public/interfaces/application",
     "//mojo/services/public/interfaces/network",
     "//mojo/shell/domain_socket",
     "//mojo/spy",
+    "//services/tracing:bindings",
+    "//url",
   ]
 
   if (is_win) {
     deps -= [
       "//mojo/shell/domain_socket",
     ]
   }
 
   if (is_android) {
     sources += [
@@ skipping 253 matching lines @@
 
     deps -= [
       ":lib",
       ":external_application_registrar_connection",
       ":external_application_registrar_bindings",
       "//mojo/shell/domain_socket",
       "//mojo/shell/domain_socket:tests",
     ]
   }
 }