Could this be related to  issue 801623 ? Currently, the presentation window is not in focus after creation, so the F11 keyboard shortcut works only after you click on the presentation window. Francois, could you confirm this is the case for you as well?

After clicking the presentation window (to focus it), I'm able to close the presentation window by pressing the [] (fullscreen) key on my keyboard.

Nit: As the Pixelbook doesn't have a F11 key (it only goes until F10), the message is not helpful though. Do you know who could be interested in solving this issue? 

I notice that when you enter fullscreen with the fullscreen key on CrOS, the toast doesn't get shown.

I think in our case (and the case of entering fullscreen via the key) we'd want to show "Press [[fullscreen key icon]] to exit fullscreen", but the toast currently takes just a string [1], so we'd have to change it to take an icon as well. I think we'd want to fix this if it's straightforward to do so.

[1] https://cs.chromium.org/chromium/src/chrome/app/generated_resources.grd?q=IDS_FULLSCREEN_PRESS_ESC_TO_EXIT_FULLSCREEN&sq=package:chromium&l=9279

I agree.

I'm not sure how difficult it would be to change the toast to an icon.  FWIW, it should be possible to hit F11 on any chromebook via Search+'-' (dash/underscore, just right of zero).  I can't confirm it works on a Pixelbook at the moment, but it works on my original Pixel.

This toast isn't usually shown (though it can be under some conditions e.g. in Kiosk mode) because immersive mode is used.  In immersive mode, the user can move the mouse to the top and get the window UI back.  I'm hesitant to remove the toast since there may be no way to get out without just _knowing_ the shortcut (e.g. on Windows).  On Chrome OS, we can definitely improve the message but I'd be okay with completely removing it there since Chromebooks have a dedicated fullscreen button.

I started https://chromium-review.googlesource.com/c/chromium/src/+/988940 for this.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0820b8e94e1313062e65241b2b92b9a557a48b71

commit 0820b8e94e1313062e65241b2b92b9a557a48b71
Author: btolsch <btolsch@chromium.org>
Date: Tue Apr 03 06:44:43 2018

Remove fullscreen toast in PresentationReceiverWindowView on Chrome OS

The text in the fullscreen exit toast is confusing on Chrome OS since it
is not commonly known how to access the F11 key.  It is not usually used
in BrowserView since immersive mode is used instead.  Additionally,
Chromebooks have a hardware fullscreen toggle button which should be
easily accessible for exiting fullscreen.

Bug:  825803 
Change-Id: I855c9920e37e4176140c874e4a7c357cc6ab3e22
Reviewed-on: https://chromium-review.googlesource.com/988940
Reviewed-by: Derek Cheng <imcheng@chromium.org>
Commit-Queue: Brandon Tolsch <btolsch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547632}
[modify] https://crrev.com/0820b8e94e1313062e65241b2b92b9a557a48b71/chrome/browser/ui/views/media_router/presentation_receiver_window_view.cc

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