Revert of Remove obsolete QUIC disabling code.

net/quic/chromium/quic_chromium_client_session.h

 // Copyright (c) 2012 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.
 //
 // A client specific QuicSession subclass.  This class owns the underlying
 // QuicConnection and QuicConnectionHelper objects.  The connection stores
 // a non-owning pointer to the helper so this session needs to ensure that
 // the helper outlives the connection.
 
 #ifndef NET_QUIC_QUIC_CHROMIUM_CLIENT_SESSION_H_
@@ skipping 40 matching lines @@
 
 namespace test {
 class QuicChromiumClientSessionPeer;
 }  // namespace test
 
 class NET_EXPORT_PRIVATE QuicChromiumClientSession
     : public QuicClientSessionBase,
       public QuicChromiumPacketReader::Visitor,
       public QuicChromiumPacketWriter::WriteErrorObserver {
  public:
+  // Reasons to 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,
+  };
+
   // An interface for observing events on a session.
   class NET_EXPORT_PRIVATE Observer {
    public:
     virtual ~Observer() {}
     virtual void OnCryptoHandshakeConfirmed() = 0;
     virtual void OnSessionClosed(int error, bool port_migration_detected) = 0;
   };
 
   // A helper class used to manage a request to create a stream.
   class NET_EXPORT_PRIVATE StreamRequest {
@@ skipping 159 matching lines @@
   // than the number of round-trips needed for the handshake.
   int GetNumSentClientHellos() const;
 
   // Returns true if |hostname| may be pooled onto this session.  If this
   // is a secure QUIC session, then |hostname| must match the certificate
   // presented during the handshake.
   bool CanPool(const std::string& hostname, PrivacyMode privacy_mode) const;
 
   const QuicServerId& server_id() const { return server_id_; }
 
+  QuicDisabledReason disabled_reason() const { return disabled_reason_; }
+
   // Migrates session onto new socket, i.e., starts reading from
   // |socket| in addition to any previous sockets, and sets |writer|
   // to be the new default writer. Returns true if socket was
   // successfully added to the session and the session was
   // successfully migrated to using the new socket. If not null,
   // |packet| is sent on the new network, else a PING frame is
   // sent. Returns true on successful migration, or false if number of
   // migrations exceeds kMaxReadersPerQuicSession.  Takes ownership of
   // |socket|, |reader|, and |writer|.
   bool MigrateToSocket(std::unique_ptr<DatagramClientSocket> socket,
@@ skipping 87 matching lines @@
   BoundNetLog net_log_;
   std::vector<std::unique_ptr<QuicChromiumPacketReader>> packet_readers_;
   base::TimeTicks dns_resolution_end_time_;
   base::TimeTicks handshake_start_;  // Time the handshake was started.
   std::unique_ptr<QuicConnectionLogger> logger_;
   // True when the session is going away, and streams may no longer be created
   // on this session. Existing stream will continue to be processed.
   bool going_away_;
   // True when the session receives a go away from server due to port migration.
   bool port_migration_detected_;
+  QuicDisabledReason disabled_reason_;
   TokenBindingSignatureMap token_binding_signatures_;
   // UMA histogram counters for streams pushed to this session.
   int streams_pushed_count_;
   int streams_pushed_and_claimed_count_;
   // Return value from packet rewrite packet on new socket. Used
   // during connection migration on socket write error.
   int error_code_from_rewrite_;
   bool use_error_code_from_rewrite_;
   base::WeakPtrFactory<QuicChromiumClientSession> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicChromiumClientSession);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CHROMIUM_CLIENT_SESSION_H_