Create a about handler component.

components/about_handler/BUILD.gn

Index: components/about_handler/BUILD.gn
diff --git a/components/error_page/common/BUILD.gn b/components/about_handler/BUILD.gn
similarity index 54%
copy from components/error_page/common/BUILD.gn
copy to components/about_handler/BUILD.gn
index 11f6ee6c9152a35a66f6fb3f60bc98ed954e3da3..7df77386ab99f9da649c5107d5e886e574fa02a9 100644
--- a/components/error_page/common/BUILD.gn
+++ b/components/about_handler/BUILD.gn
@@ -2,16 +2,16 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-static_library("common") {
+static_library("about_handler") {
   sources = [
-    "error_page_params.cc",
-    "error_page_params.h",
-    "net_error_info.cc",
-    "net_error_info.h",
+    "about_protocol_handler.cc",
+    "about_protocol_handler.h",
+    "url_request_about_job.cc",
+    "url_request_about_job.h",
   ]
 
   deps = [
     "//base",
-    "//url",
+    "//net",
   ]
 }