The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3917d71d9560fcd683bc0b79b838e3abb57aec50

commit 3917d71d9560fcd683bc0b79b838e3abb57aec50
Author: Egor Pasko <pasko@chromium.org>
Date: Mon Aug 21 10:21:38 2017

Prerender: remove tests for EmbeddedSearch field trial

The field trial itself is being removed concurrently by treib@.

Bug:  757381 
Change-Id: Ia0f06d43640775a6cf372b72f02248b37add2a06
Reviewed-on: https://chromium-review.googlesource.com/623207
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495903}
[modify] https://crrev.com/3917d71d9560fcd683bc0b79b838e3abb57aec50/chrome/browser/prerender/prerender_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/15a21195e7bf96ea7f20cb8f0225f352497c9452

commit 15a21195e7bf96ea7f20cb8f0225f352497c9452
Author: Egor Pasko <pasko@chromium.org>
Date: Mon Aug 21 15:44:12 2017

Prerender: Remove PrerenderSilence experiment

We planned using this experiment as part of the deprecation process for
Prerender, but it never was enabled on Stable. For the remaining uses of
Prerender there are other dedicated experiments, hence this one can be removed.

Bug:  757381 
Change-Id: Ia095437334ebd887e180c23a22dcbce1227bed3d
Reviewed-on: https://chromium-review.googlesource.com/623527
Commit-Queue: Egor Pasko <pasko@chromium.org>
Reviewed-by: Matthew Cary <mattcary@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495943}
[modify] https://crrev.com/15a21195e7bf96ea7f20cb8f0225f352497c9452/chrome/browser/prerender/prerender_manager.cc
[modify] https://crrev.com/15a21195e7bf96ea7f20cb8f0225f352497c9452/chrome/browser/prerender/prerender_manager.h
[modify] https://crrev.com/15a21195e7bf96ea7f20cb8f0225f352497c9452/chrome/browser/prerender/prerender_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f6bc168a3206f5f4bd775cfefcefb6cb2af8b043

commit f6bc168a3206f5f4bd775cfefcefb6cb2af8b043
Author: Egor Pasko <pasko@chromium.org>
Date: Tue Aug 22 16:13:21 2017

Prerender: remove the PrerenderRelNextTrial

The trial expired years ago and did not find noticeable speedups.
Removing the trial, but keeping the histograms to track <link rel=next>
usage on the web.

Bug:  757381 
Change-Id: I470b808b1bd3f1b5371e93f86bc657ccbcd2e9ae
Reviewed-on: https://chromium-review.googlesource.com/623648
Reviewed-by: Matthew Cary <mattcary@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Commit-Queue: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496321}
[modify] https://crrev.com/f6bc168a3206f5f4bd775cfefcefb6cb2af8b043/chrome/browser/prerender/prerender_link_manager.cc
[modify] https://crrev.com/f6bc168a3206f5f4bd775cfefcefb6cb2af8b043/chrome/browser/prerender/prerender_unittest.cc
[modify] https://crrev.com/f6bc168a3206f5f4bd775cfefcefb6cb2af8b043/third_party/WebKit/Source/core/exported/PrerenderingTest.cpp
[delete] https://crrev.com/25e96490d3362bdcf07dbb28f5c481dab080409f/third_party/WebKit/Source/core/testing/data/prerender/rel_next_prerender.html

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337

commit 5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337
Author: Egor Pasko <pasko@chromium.org>
Date: Wed Aug 23 10:05:49 2017

Prerender: remove the PrerenderFromOmnibox field trial

The field trial is long unused. It also has become unnecessary, since
disabling Omnibox prerenders/prefetches is possible via the
kNoStatePrefetchFeature.

Also removing the corresponding commandline flag, as described in [1].

[1] NoState Prefetch: Manually setting the prefetch mode:
    http://goo.gl/EJjTCM#bookmark=id.brkm50l4fxog

Bug:  757381 
Change-Id: Ida231b0a321aba464ef96c8aacca4d7156fe15c4
Reviewed-on: https://chromium-review.googlesource.com/626117
Reviewed-by: Matthew Cary <mattcary@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496645}
[modify] https://crrev.com/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337/chrome/browser/android/chrome_startup_flags.cc
[modify] https://crrev.com/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337/chrome/browser/predictors/autocomplete_action_predictor_unittest.cc
[modify] https://crrev.com/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337/chrome/browser/prerender/prerender_field_trial.cc
[modify] https://crrev.com/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337/chrome/browser/prerender/prerender_unittest.cc
[modify] https://crrev.com/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337/chrome/common/chrome_switches.cc
[modify] https://crrev.com/5fb4a8cb0d99040c1dc2ee10d12f58b7d4f77337/chrome/common/chrome_switches.h

I was considering removing some PrerenderRelNextTrial histograms, but after a closer look decided against it. Other histograms will be removed as part of other cleanup.