_
Tao, can you please take a look?

It works on EVE of the version chrome 67.0.3394.0/platform 10560.0.0.

Could be very recent regression.

My eve with 66.0.3359.79 has the same issue. just fyi.

Alt + Tab works on my emulator.

In #2, I changed the accelerator to Ctrl + Tab, it works. But when I change back to Alt + Tab, it does not work.

Do we know does this ever worked? I installed the image of R64-10166.0.0, this was broken since then.

My current investigation is that focus_manager consumes it as a "Tab" traversal key event. The last modification of the focus_manager [1] was back to year 2012.

In accelerator_router, for fullscreen window, we let chrome to process the accelerator first and then the Window cycling [2]. But somehow the focus_manager of task_manger_view consumes it as "Tab":

[1] https://cs.chromium.org/chromium/src/ui/views/focus/focus_manager.cc?l=66&rcl=9626747364df824453684d268085d9922844f81b

[2] https://cs.chromium.org/chromium/src/ash/accelerators/accelerator_router.cc?l=121&rcl=cdf4606b9631e94d9b99255ff4e4091657d2fb42

Hi Oshima, WDYT?

We can fix this by modifying the focus_manager [1]:

bool FocusManager::IsTabTraversalKeyEvent(const ui::KeyEvent& key_event) {
  return key_event.key_code() == ui::VKEY_TAB &&
         (!key_event.IsControlDown() && !key_event.IsAltDown());
}


[1] https://cs.chromium.org/chromium/src/ui/views/focus/focus_manager.cc?l=487&rcl=63e1deefefdd3079852438f5e8db63b46afeb259

i see. thank you for looking into this.

#6 sgtm

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/42d3c3dc87ff12584cf07d02b2433a6ca55d7366

commit 42d3c3dc87ff12584cf07d02b2433a6ca55d7366
Author: wutao <wutao@chromium.org>
Date: Tue Apr 17 17:36:32 2018

Fix alt-tab on fullscreen task manager

Currently for fullscreen window, Ash lets the browser or apps to process
the accelerator first. However, focus_manager handles "alt-tab" as a
"Tab" traversal key event. This cl fixes this bug.

Bug:  832739 
Test: New test FocusManagerTest.IsTabTraversalKeyEvent
Change-Id: I6252a5614390223c581d032d39dbad1c84de6b48
Reviewed-on: https://chromium-review.googlesource.com/1014651
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551377}
[modify] https://crrev.com/42d3c3dc87ff12584cf07d02b2433a6ca55d7366/ui/views/focus/focus_manager.cc
[modify] https://crrev.com/42d3c3dc87ff12584cf07d02b2433a6ca55d7366/ui/views/focus/focus_manager_unittest.cc