Use overloaded operators with QuicTime for addition, subtraction and scalar

net/quic/quic_flow_controller.cc

 // 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.
 
 #include "net/quic/quic_flow_controller.h"
 
 #include "base/strings/stringprintf.h"
 #include "net/quic/quic_bug_tracker.h"
 #include "net/quic/quic_connection.h"
 #include "net/quic/quic_flags.h"
@@ skipping 117 matching lines @@
 
   // Get outbound RTT.
   QuicTime::Delta rtt =
       connection_->sent_packet_manager().GetRttStats()->smoothed_rtt();
   if (rtt.IsZero()) {
     DVLOG(1) << ENDPOINT << "rtt zero for stream " << id_;
     return;
   }
 
   // Now we can compare timing of window updates with RTT.
-  QuicTime::Delta since_last = now.Subtract(prev);
-  QuicTime::Delta two_rtt = rtt.Multiply(2);
+  QuicTime::Delta since_last = now - prev;
+  QuicTime::Delta two_rtt = 2 * rtt;
 
   if (since_last >= two_rtt) {
     // If interval between window updates is sufficiently large, there
     // is no need to increase receive_window_size_.
     return;
   }
 
   QuicByteCount old_window = receive_window_size_;
   receive_window_size_ *= 2;
   receive_window_size_ =
@@ skipping 99 matching lines @@
   if (receive_window_size_ != receive_window_offset_) {
     QUIC_BUG << "receive_window_size_:" << receive_window_size_
              << " != receive_window_offset:" << receive_window_offset_;
     return;
   }
   receive_window_size_ = size;
   receive_window_offset_ = size;
 }
 
 }  // namespace net