[Startup Tracing] Enable startup tracing from config file

mojo/runner/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("//mojo/generate_mojo_shell_assets_list.gni")
 import("//mojo/public/mojo_application.gni")
 import("//testing/test.gni")
 import("//third_party/mojo/src/mojo/public/tools/bindings/mojom.gni")
 
 # We don't support building in the component build since mojo apps are
@@ skipping 27 matching lines @@
     "//mojo/common",
     "//mojo/environment:chromium",
   ]
 
   if (!is_android) {
     sources += [
       "desktop/launcher_process.cc",
       "desktop/launcher_process.h",
       "desktop/main.cc",
     ]
+    deps += [ "//components/tracing:startup_tracing" ]
   } else {
     sources += [
       "android/context_init.h",
       "android/library_loader.cc",
       "android/main.cc",
       "android/main.h",
     ]
 
     deps += [
       ":jni_headers",
@@ skipping 385 matching lines @@
   ]
 
   deps = [
     "//base",
     "//mojo/application/public/cpp:test_support",
     "//mojo/runner/test:bindings",
     "//mojo/services/network/public/interfaces",
     "//third_party/mojo/src/mojo/public/cpp/bindings:callback",
   ]
 }