QUIC - disable QUIC under recent pathological connection errors.

net/quic/quic_types.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_QUIC_TYPES_H_
 #define NET_QUIC_QUIC_TYPES_H_
 
 // This header defines some basic types that don't depend on quic_protocol.h,
 // so that classes not directly related to the protocol wire format can avoid
 // including quic_protocol.h.
@@ skipping 33 matching lines @@
   QUIC_PENDING = 2,
 };
 
 // TODO(wtc): see if WriteStatus can be replaced by QuicAsyncStatus.
 enum WriteStatus {
   WRITE_STATUS_OK,
   WRITE_STATUS_BLOCKED,
   WRITE_STATUS_ERROR,
 };
 
+// Reasons we may disable QUIC, that is under certain pathological
+// connection errors.  Note: these values must be kept in sync with
+// the corresponding values of QuicDisabledReason in:
+// tools/metrics/histograms/histograms.xml
+enum QuicDisabledReason {
+  QUIC_DISABLED_NOT = 0,  // default, not disabled
+  QUIC_DISABLED_PUBLIC_RESET_POST_HANDSHAKE = 1,
+  QUIC_DISABLED_TIMEOUT_WITH_OPEN_STREAMS = 2,
+  QUIC_DISABLED_BAD_PACKET_LOSS_RATE = 3,
+  QUIC_DISABLED_MAX = 4,
+};
+
 // A struct used to return the result of write calls including either the number
 // of bytes written or the error code, depending upon the status.
 struct NET_EXPORT_PRIVATE WriteResult {
   WriteResult(WriteStatus status, int bytes_written_or_error_code);
   WriteResult();
 
   WriteStatus status;
   union {
     int bytes_written;  // only valid when status is WRITE_STATUS_OK
     int error_code;  // only valid when status is WRITE_STATUS_ERROR
   };
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_TYPES_H_