Create a about handler component.

components/about_handler/BUILD.gn

 # Copyright 2015 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.
 
-source_set("launcher_support") {
+source_set("about_handler") {
   sources = [
-    "chrome_launcher_support.cc",
-    "chrome_launcher_support.h",
+    "about_protocol_handler.cc",
+    "about_protocol_handler.h",
+    "url_request_about_job.cc",
+    "url_request_about_job.h",
   ]
 
   deps = [
     "//base",
+    "//net",
   ]
 }