The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c79d3f509529c663bc208363ade6441bcfc6b783

commit c79d3f509529c663bc208363ade6441bcfc6b783
Author: rtenneti <rtenneti@chromium.org>
Date: Wed Aug 10 18:34:56 2016

QUIC - Added histograms to track how cache ie performing when server
configs are stored in the prefs.json file by cronet.

The following histrograms are usefule for cronet based apps.

Net.QuicDiskCache.APICall.PropertiesBasedCache
Net.QuicDiskCache.FailureReason.PropertiesBasedCache

BUG= 636049 
R=asvitkine@chromium.org,rch@chromium.org, rkaplow@chromium.org

Review-Url: https://codereview.chromium.org/2230503003
Cr-Commit-Position: refs/heads/master@{#411092}

[modify] https://crrev.com/c79d3f509529c663bc208363ade6441bcfc6b783/net/http/disk_cache_based_quic_server_info.h
[modify] https://crrev.com/c79d3f509529c663bc208363ade6441bcfc6b783/net/quic/chromium/quic_stream_factory.cc
[modify] https://crrev.com/c79d3f509529c663bc208363ade6441bcfc6b783/net/quic/core/crypto/properties_based_quic_server_info.cc
[modify] https://crrev.com/c79d3f509529c663bc208363ade6441bcfc6b783/net/quic/core/crypto/quic_server_info.h
[modify] https://crrev.com/c79d3f509529c663bc208363ade6441bcfc6b783/tools/metrics/histograms/histograms.xml