Leverage profile's http network session's HttpAuthCache to support proxy auth.

components/gcm_driver/gcm_client_impl.h

Index: components/gcm_driver/gcm_client_impl.h
diff --git a/components/gcm_driver/gcm_client_impl.h b/components/gcm_driver/gcm_client_impl.h
index 0ce19d6d6cf91e61a5456747864c1b6fc01bb735..a0167325371cdc130e554bfab9467be68540a8d3 100644
--- a/components/gcm_driver/gcm_client_impl.h
+++ b/components/gcm_driver/gcm_client_impl.h
@@ -64,7 +64,8 @@ class GCMInternalsBuilder {
   virtual scoped_ptr<ConnectionFactory> BuildConnectionFactory(
       const std::vector<GURL>& endpoints,
       const net::BackoffEntry::Policy& backoff_policy,
-      scoped_refptr<net::HttpNetworkSession> network_session,
+      const scoped_refptr<net::HttpNetworkSession>& http_network_session,
+      const scoped_refptr<net::HttpNetworkSession>& gcm_network_session,
       net::NetLog* net_log,
       GCMStatsRecorder* recorder);
 };