Server push cancellation: clean up the code to make sure shared code is in sync with internal code.

net/quic/core/quic_client_promised_info.cc

Index: net/quic/core/quic_client_promised_info.cc
diff --git a/net/quic/core/quic_client_promised_info.cc b/net/quic/core/quic_client_promised_info.cc
index 6c099b379e38d8e3c85448e2cc76308ac6c9e10f..1648a2bc9d6e2e6d03c8147199d5df672580c09e 100644
--- a/net/quic/core/quic_client_promised_info.cc
+++ b/net/quic/core/quic_client_promised_info.cc
@@ -113,6 +113,10 @@ QuicAsyncStatus QuicClientPromisedInfo::HandleClientRequest(
   }
 
   if (is_validating()) {
+    // The push promise has already been matched to another request though
+    // pending for validation. Returns QUIC_FAILURE to the caller as it couldn't
+    // match a new request any more. This will not affect the validation of the
+    // other request.
     return QUIC_FAILURE;
   }