Fix web_accesible_resources enforcement for Site Isolation.

extensions/browser/extension_protocols.cc

Index: extensions/browser/extension_protocols.cc
diff --git a/extensions/browser/extension_protocols.cc b/extensions/browser/extension_protocols.cc
index c97f172607acbc2650537d6895a60a5704da4208..0ae21efbf1cf15bc60b61bc88cce195206b79209 100644
--- a/extensions/browser/extension_protocols.cc
+++ b/extensions/browser/extension_protocols.cc
@@ -422,8 +422,8 @@ ExtensionProtocolHandler::MaybeCreateJob(
   // TODO(mpcomplete): better error code.

[Devlin, 2016/06/06 22:17:22]

Is this considered a better error code? :)

[nasko, 2016/06/06 23:23:03]

I don't know : ), hence why I left the comment. I can yank it if you think it is
better now.

   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.