CL at https://chromium-review.googlesource.com/c/chromium/src/+/848236

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/598a4a477eda64bfe93f07c66913e93ecaf44684

commit 598a4a477eda64bfe93f07c66913e93ecaf44684
Author: Dave Schuyler <dschuyler@chromium.org>
Date: Thu Jan 04 20:42:39 2018

[Rich Entity Suggest] add flag for omnibox-rich-entity-suggest

This CL adds a flag for enable/disable the GUI enhancements for rich
entity suggestions in the omnibox. The default value is Disabled.

As of this CL, the flag has no effect.

Bug:  798630 
Change-Id: I9e3ca0660965019dfbab16d2b98255d8cf7128c0
Reviewed-on: https://chromium-review.googlesource.com/848236
Commit-Queue: Dave Schuyler <dschuyler@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527085}
[modify] https://crrev.com/598a4a477eda64bfe93f07c66913e93ecaf44684/chrome/browser/about_flags.cc
[modify] https://crrev.com/598a4a477eda64bfe93f07c66913e93ecaf44684/chrome/browser/flag_descriptions.cc
[modify] https://crrev.com/598a4a477eda64bfe93f07c66913e93ecaf44684/chrome/browser/flag_descriptions.h
[modify] https://crrev.com/598a4a477eda64bfe93f07c66913e93ecaf44684/components/omnibox/browser/omnibox_field_trial.cc
[modify] https://crrev.com/598a4a477eda64bfe93f07c66913e93ecaf44684/components/omnibox/browser/omnibox_field_trial.h
[modify] https://crrev.com/598a4a477eda64bfe93f07c66913e93ecaf44684/tools/metrics/histograms/enums.xml