The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b4b59de15639559e9fbdc818d3ca1ca960dbc0c0

commit b4b59de15639559e9fbdc818d3ca1ca960dbc0c0
Author: afakhry <afakhry@chromium.org>
Date: Fri Mar 31 05:02:14 2017

Send UMA about requested window state from tabs API

As part of the deprecation of docked windows, we need to record some
UMA stats to track the number of times the "docked" window state was
requested, so that we can remove it at the appropriate milestone.

BUG= 703733 

Review-Url: https://codereview.chromium.org/2779683004
Cr-Commit-Position: refs/heads/master@{#461044}

[modify] https://crrev.com/b4b59de15639559e9fbdc818d3ca1ca960dbc0c0/chrome/browser/extensions/api/tabs/tabs_api.cc
[modify] https://crrev.com/b4b59de15639559e9fbdc818d3ca1ca960dbc0c0/chrome/common/extensions/api/windows.json
[modify] https://crrev.com/b4b59de15639559e9fbdc818d3ca1ca960dbc0c0/tools/metrics/histograms/histograms.xml

Thanks!  Can we either repurpose this bug or file a new one for actually removing the enum, if UMA indicates we can?

Done. Filed Issue 707260.