Componentize proxy code from chrome/browser/net

components/proxy_config/BUILD.gn

Index: components/proxy_config/BUILD.gn
diff --git a/components/proxy_config/BUILD.gn b/components/proxy_config/BUILD.gn
index 439fd305351699aaa8c4265afc7bee1e2adbbd6c..8db372bb3be40264dc38e004ecbdd4c3d8a81792 100644
--- a/components/proxy_config/BUILD.gn
+++ b/components/proxy_config/BUILD.gn
@@ -5,9 +5,15 @@
 # GYP version: components/proxy_config.gypi:proxy_config_component
 component("proxy_config") {
   sources = [
+    "pref_proxy_config_tracker.cc",
+    "pref_proxy_config_tracker.h",
+    "pref_proxy_config_tracker_impl.cc",
+    "pref_proxy_config_tracker_impl.h",
     "proxy_config_dictionary.cc",
     "proxy_config_dictionary.h",
     "proxy_config_export.h",
+    "proxy_config_pref_names.cc",
+    "proxy_config_pref_names.h",
     "proxy_prefs.cc",
     "proxy_prefs.h",
   ]
@@ -16,6 +22,7 @@ component("proxy_config") {
 
   deps = [
     "//base",
+    "//components/pref_registry",
     "//net",
   ]
 }