Fix web_accesible_resources enforcement for Site Isolation.

extensions/browser/extension_protocols.cc

 // 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.
 
 #include "extensions/browser/extension_protocols.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 401 matching lines @@
 
 // Creates URLRequestJobs for extension:// URLs.
 net::URLRequestJob*
 ExtensionProtocolHandler::MaybeCreateJob(
     net::URLRequest* request, net::NetworkDelegate* network_delegate) const {
   // chrome-extension://extension-id/resource/path.js
   std::string extension_id = request->url().host();
   const Extension* extension =
       extension_info_map_->extensions().GetByID(extension_id);
 
-  // TODO(mpcomplete): better error code.
   if (!AllowExtensionResourceLoad(
           request, is_incognito_, extension, extension_info_map_)) {
-    return new net::URLRequestErrorJob(
-        request, network_delegate, net::ERR_ADDRESS_UNREACHABLE);
+    return new net::URLRequestErrorJob(request, network_delegate,
+                                       net::ERR_BLOCKED_BY_CLIENT);
   }
 
   // If this is a disabled extension only allow the icon to load.
   base::FilePath directory_path;
   if (extension)
     directory_path = extension->path();
   if (directory_path.value().empty()) {
     const Extension* disabled_extension =
         extension_info_map_->disabled_extensions().GetByID(extension_id);
     if (URLIsForExtensionIcon(request->url(), disabled_extension))
@@ skipping 140 matching lines @@
 }
 
 std::unique_ptr<net::URLRequestJobFactory::ProtocolHandler>
 CreateExtensionProtocolHandler(bool is_incognito,
                                extensions::InfoMap* extension_info_map) {
   return base::WrapUnique(
       new ExtensionProtocolHandler(is_incognito, extension_info_map));
 }
 
 }  // namespace extensions