ResourceResponse: Fix self-assignment in DeepCopy().

Fix what looks like a copy-paste error in the assignment of
|was_alternate_protocol_available|.

Review URL: https://codereview.chromium.org/941973004

Cr-Commit-Position: refs/heads/master@{#317374}

content/public/common/resource_response.cc

@@ -31,7 +31,7 @@ scoped_refptr<ResourceResponse> ResourceResponse::DeepCopy() const {
   new_response->head.was_fetched_via_spdy = head.was_fetched_via_spdy;
   new_response->head.was_npn_negotiated = head.was_npn_negotiated;
   new_response->head.was_alternate_protocol_available =
-      new_response->head.was_alternate_protocol_available;
+      head.was_alternate_protocol_available;
   new_response->head.connection_info = head.connection_info;
   new_response->head.was_fetched_via_proxy = head.was_fetched_via_proxy;
   new_response->head.proxy_server = head.proxy_server;