Introduce NetworkDelegate's implementation in extensions.

extensions/browser/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/crypto.gni")
 import("//build/config/features.gni")
 
 # GYP version: extensions/extensions.gyp:extensions_browser
 source_set("browser") {
   sources = [
@@ skipping 286 matching lines @@
       "extension_function_registry.h",
       "extension_function_util.cc",
       "extension_function_util.h",
       "extension_host.cc",
       "extension_host.h",
       "extension_host_delegate.h",
       "extension_icon_image.cc",
       "extension_icon_image.h",
       "extension_message_filter.cc",
       "extension_message_filter.h",
+      "extension_network_delegate.cc",
+      "extension_network_delegate.h",
       "extension_pref_store.cc",
       "extension_pref_store.h",
       "extension_pref_value_map.cc",
       "extension_pref_value_map.h",
       "extension_pref_value_map_factory.cc",
       "extension_pref_value_map_factory.h",
       "extension_prefs.cc",
       "extension_prefs.h",
       "extension_prefs_factory.cc",
       "extension_prefs_factory.h",
       "extension_prefs_observer.h",
       "extension_prefs_scope.h",
       "extension_protocols.cc",
       "extension_protocols.h",
       "extension_registry.cc",
       "extension_registry.h",
       "extension_registry_factory.cc",
       "extension_registry_factory.h",
       "extension_registry_observer.h",
       "extension_scoped_prefs.h",
       "extension_system.cc",
       "extension_system.h",
       "extension_system_provider.cc",
       "extension_system_provider.h",
+      "extension_url_request_context_getter.cc",
+      "extension_url_request_context_getter.h",
       "extension_util.cc",
       "extension_util.h",
       "extension_web_contents_observer.cc",
       "extension_web_contents_observer.h",
       "extensions_browser_client.cc",
       "extensions_browser_client.h",
       "external_provider_interface.h",
       "file_highlighter.cc",
       "file_highlighter.h",
       "file_reader.cc",
@@ skipping 126 matching lines @@
       ]
     }
   }
 
   if (is_win) {
     cflags = [
       "/wd4267", # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     ]
   }
 }