Land recent QUIC changes.

net/quic/quic_clock.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.
 
 #ifndef NET_QUIC_QUIC_CLOCK_H_
 #define NET_QUIC_QUIC_CLOCK_H_
 
 #include "base/basictypes.h"
 #include "net/base/net_export.h"
 #include "net/quic/quic_time.h"
 
 namespace net {
 
 typedef double WallTime;
 
 // Clock to efficiently retrieve an approximately accurate time from an
 // EpollServer.
 class NET_EXPORT_PRIVATE QuicClock {
  public:
   QuicClock();
   virtual ~QuicClock();
 
   // Returns the approximate current time as a QuicTime object.
+  virtual QuicTime ApproximateNow() const;
+
+  // Returns the current time as a QuicTime object.
+  // Note: this use significant resources please use only if needed.
   virtual QuicTime Now() const;
 
   // Returns the current time as an offset from the Unix epoch (1970-01-01
   // 00:00:00 GMT). This function may return a smaller Delta in subsequent
   // calls if the system clock is changed.
   virtual QuicTime::Delta NowAsDeltaSinceUnixEpoch() const;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CLOCK_H_