Allow embedder to use custom ResourceRequestAllowedNotifier

By allowing custom ResourceRequestAllowedNotifier, embedder
has the flexibility to set custom criteria when the fetch is
allowed or not allowed.

BUG=634458

Review-Url: https://codereview.chromium.org/2217683002
Cr-Commit-Position: refs/heads/master@{#454739}
diff --git a/AUTHORS b/AUTHORS
index dc45a9a..56667bc 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -82,6 +82,7 @@
 Arunoday Sarkar <[email protected]>
 Arunprasad Rajkumar <[email protected]>
 Arunprasad Rajkumar <[email protected]>
+Ashish Kumar Gupta <[email protected]>
 Ashlin Joseph <[email protected]>
 Attila Dusnoki <[email protected]>
 Avinaash Doreswamy <[email protected]>