Add three new histogram to tracking QUIC packet reordering:

net/quic/quic_client_session.cc

 // 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.
 
 #include "net/quic/quic_client_session.h"
 
 #include "base/callback_helpers.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
@@ skipping 225 matching lines @@
     }
   } else {
     if (port_selected) {
       UMA_HISTOGRAM_CUSTOM_COUNTS("Net.QuicSession.ConnectSelectPortForHTTPS",
                                   round_trip_handshakes, 0, 3, 4);
     } else {
       UMA_HISTOGRAM_CUSTOM_COUNTS("Net.QuicSession.ConnectRandomPortForHTTPS",
                                   round_trip_handshakes, 0, 3, 4);
     }
   }
+  const QuicConnectionStats stats = connection()->GetStats();
+  uint64 reordering =
+      GG_UINT64_C(100) * stats.max_time_reordering_us / stats.min_rtt_us;
+    UMA_HISTOGRAM_CUSTOM_COUNTS("Net.QuicSession.MaxReorderingTime",
+                                reordering, 0, 100, 101);
+  if (stats.min_rtt_us > 100) {
+    UMA_HISTOGRAM_CUSTOM_COUNTS("Net.QuicSession.MaxReorderingTimeLongRtt",
+                                reordering, 0, 100, 101);
+  }
 }
 
 void QuicClientSession::OnStreamFrames(
     const std::vector<QuicStreamFrame>& frames) {
   // Record total number of stream frames.
   UMA_HISTOGRAM_COUNTS("Net.QuicNumStreamFramesInPacket", frames.size());
 
   // Record number of frames per stream in packet.
   typedef std::map<QuicStreamId, size_t> FrameCounter;
   FrameCounter frames_per_stream;
@@ skipping 521 matching lines @@
     RecordUnexpectedNotGoingAway(NOTIFY_FACTORY_OF_SESSION_CLOSED);
 
   going_away_ = true;
   DCHECK_EQ(0u, GetNumOpenStreams());
   // Will delete |this|.
   if (stream_factory_)
     stream_factory_->OnSessionClosed(this);
 }
 
 }  // namespace net