+sdantuluri@ is this only happen with the sequence in #1
otherwise you can browse as guest ?

Re c#3: No particular sequence. I will edit the description to be clear.

Just to confirm, this only happens on 10279.0.0, 65.0.3311.0 and not on 10278.0.0, 65.0.3299.0?

This will block dev on the newer Chrome until this is resolved. 

Albert, can you help triage this?

Re c#6: Yes, this happens only on 10279.0.0, 65.0.3311.0. No repro on 10278.0.0, 65.0.3299.0

 Issue 799378  has been merged into this issue.

Manually verified that this is caused by https://chromium-review.googlesource.com/c/832919/

 Issue 800108  has been merged into this issue.

I am still experiencing this issue on a Sumo Device using the following build

Chrome OS 10295.0.0, 65.0.3316.0

 Issue 799836  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3975aa9d24cdf777a63596c4e4e31fd1b3803fc2

commit 3975aa9d24cdf777a63596c4e4e31fd1b3803fc2
Author: Aga Wronska <agawronska@chromium.org>
Date: Wed Jan 10 23:59:13 2018

Hide ShelfWidget when web UI shelf is used.

Having ShelfWidget shown was preventing  web UI shelf from receiving
mouse events. Widget when shown, even when inactive was consuming
mouse events (keyboard events were passed correctly).

ShelfWidget is not shown in UNKNOWN state, because it might not be
initialized then.

Bug:  799292 
Change-Id: I4c8074454be4885add89d3a7e79cdbbb4760db33
Reviewed-on: https://chromium-review.googlesource.com/853196
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528494}
[modify] https://crrev.com/3975aa9d24cdf777a63596c4e4e31fd1b3803fc2/ash/shelf/shelf_widget.cc
[modify] https://crrev.com/3975aa9d24cdf777a63596c4e4e31fd1b3803fc2/ash/shelf/shelf_widget.h
[modify] https://crrev.com/3975aa9d24cdf777a63596c4e4e31fd1b3803fc2/ash/shelf/shelf_widget_unittest.cc

Verified cros: 10302.0.0/65.0.3319.0