The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f2113bc361ed6ad09f2e97ef5068be4e8c32e114

commit f2113bc361ed6ad09f2e97ef5068be4e8c32e114
Author: csharrison <csharrison@chromium.org>
Date: Wed Jun 29 15:07:55 2016

Don't clear the net predictors prefs on startup

Traditionally, the net predictor had its database cleared from preferences
during startup, deleting them while transfering to a completely in-memory
representation.

This is non-ideal for Android, where unclean shutdowns are more common due
to oom-killer.

This patch removes the behavior in favor of clearing the prefs when the user
clears browsing history. Note that in order to properly persist db updates
in the presence of unclean shutdowns, we will have to sync the prefs more
often. This will be implemented as a follow up.

BUG= 621604 

Review-Url: https://codereview.chromium.org/2085643002
Cr-Commit-Position: refs/heads/master@{#402813}

[modify] https://crrev.com/f2113bc361ed6ad09f2e97ef5068be4e8c32e114/chrome/browser/browsing_data/browsing_data_remover.cc
[modify] https://crrev.com/f2113bc361ed6ad09f2e97ef5068be4e8c32e114/chrome/browser/chrome_net_benchmarking_message_filter.cc
[modify] https://crrev.com/f2113bc361ed6ad09f2e97ef5068be4e8c32e114/chrome/browser/chrome_net_benchmarking_message_filter.h
[modify] https://crrev.com/f2113bc361ed6ad09f2e97ef5068be4e8c32e114/chrome/browser/net/predictor.cc
[modify] https://crrev.com/f2113bc361ed6ad09f2e97ef5068be4e8c32e114/chrome/browser/net/predictor.h
[modify] https://crrev.com/f2113bc361ed6ad09f2e97ef5068be4e8c32e114/chrome/browser/net/predictor_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ee45633faa3fae0320db4b630ec24221e930478e

commit ee45633faa3fae0320db4b630ec24221e930478e
Author: csharrison <csharrison@chromium.org>
Date: Mon Aug 01 19:20:03 2016

Use lossy prefs in the net predictor, and update them more frequently

This patch changes the predictor to use lossy prefs to sync referrer lists,
and updates them upon receiving the load event from a main frame document.

This fixes an issue where prefs are not updated on unclean shutdown, and
a hang during a synchronous thread hop roundtrip.

BUG= 78451 , 621604 

Review-Url: https://codereview.chromium.org/2084093002
Cr-Commit-Position: refs/heads/master@{#409017}

[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/net/predictor.cc
[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/net/predictor.h
[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/net/predictor_browsertest.cc
[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/net/predictor_tab_helper.cc
[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/net/predictor_tab_helper.h
[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/net/predictor_unittest.cc
[modify] https://crrev.com/ee45633faa3fae0320db4b630ec24221e930478e/chrome/browser/profiles/profile_impl_io_data.cc