[Startup Tracing] Enable startup tracing from config file

content/common/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("//build/config/ui.gni")
 import("//content/common/common.gni")
 import("//third_party/mojo/src/mojo/public/tools/bindings/mojom.gni")
 
 if (is_chromeos && current_cpu != "arm") {
@@ skipping 125 matching lines @@
   ]
 
   public_deps = [
     "//gpu/command_buffer/common",
     "//third_party/WebKit/public:blink_headers",
   ]
   deps = [
     "//base",
     "//build/util:webkit_version",
     "//components/tracing",
+    "//components/tracing:startup_tracing",
     "//gpu/command_buffer/client:gles2_interface",
     "//gpu/command_buffer/common:gles2_utils",
     "//net",
     "//skia",
     "//third_party/icu",
     "//ui/accessibility",
     "//ui/base",
     "//ui/base/ime",
     "//ui/events/ipc",
     "//ui/gfx",
@@ skipping 338 matching lines @@
     "render_frame_setup.mojom",
   ]
 
   import_dirs = [ "//mojo/services" ]
 
   deps = [
     "//content/public/common:mojo_bindings",
     "//mojo/application/public/interfaces",
   ]
 }