The launch id string is encoded by us, so I am a bit confused why it cannot be decoded correctly. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/91695ae4ffcb13db2fb6df061d198d7474d32871

commit 91695ae4ffcb13db2fb6df061d198d7474d32871
Author: Xi Cheng <chengx@chromium.org>
Date: Sat May 05 00:34:43 2018

Dedup enums in Notifications.Windows.ActivationStatus

Methods GetProfileIdFromLaunchId() and HandleActivation() are both called
in a single notification activation run. They log the same failure to UMA,
which skews the UMA failure metrics. This CL fixes it.

Bug:  734095 ,  839942 
Change-Id: If7e7cd63869a19b815052bd2b470577e06660252
Reviewed-on: https://chromium-review.googlesource.com/1040349
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Finnur Thorarinsson <finnur@chromium.org>
Commit-Queue: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556272}
[modify] https://crrev.com/91695ae4ffcb13db2fb6df061d198d7474d32871/chrome/browser/notifications/notification_platform_bridge_win.cc
[modify] https://crrev.com/91695ae4ffcb13db2fb6df061d198d7474d32871/chrome/browser/notifications/notification_platform_bridge_win_metrics.h
[modify] https://crrev.com/91695ae4ffcb13db2fb6df061d198d7474d32871/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/91695ae4ffcb13db2fb6df061d198d7474d32871/tools/metrics/histograms/histograms.xml

Now Notifications.Windows.ActivationStatus only has two enums: SUCCESS and INVALID_LAUNCH_ID.

Hi Finnur, do you have any insights here? Thanks!

Hmm, hard to say. It could be non-existent (blank) or garbled or invalid in some other way. Maybe the contents of notification_id is messing up the parsing... 

As for why that would be, I have no idea. But we could get more info by adding INVALID_LAUNCH_ID_BLANK and/or adding metrics to the parsing code (NotificationLaunchId dtor that takes a string as param)...

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fa67db5c1a6e20836650aa14e15f7a6507a44da0

commit fa67db5c1a6e20836650aa14e15f7a6507a44da0
Author: Xi Cheng <chengx@chromium.org>
Date: Wed May 23 20:50:39 2018

Log notification launch id decode status

We have ~1% invalid launch ids that are invalid, which needs more investigation.

Bug:  839942 ,  734095 
Change-Id: Ibebb6beeebb6fe4200d49a728dde56d979a795cc
Reviewed-on: https://chromium-review.googlesource.com/1068655
Commit-Queue: Xi Cheng <chengx@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Finnur Thorarinsson <finnur@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561249}
[modify] https://crrev.com/fa67db5c1a6e20836650aa14e15f7a6507a44da0/chrome/browser/notifications/notification_launch_id.cc
[modify] https://crrev.com/fa67db5c1a6e20836650aa14e15f7a6507a44da0/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/fa67db5c1a6e20836650aa14e15f7a6507a44da0/tools/metrics/histograms/histograms.xml

Quick update: 

According to Notifications.Windows.LaunchIdDecodeStatus metric data, the only failure reason is that the launch id string is empty.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d326a008e79cb49bdc3871e08bf3fb8ef902b871

commit d326a008e79cb49bdc3871e08bf3fb8ef902b871
Author: Xi Cheng <chengx@chromium.org>
Date: Wed May 30 03:53:55 2018

Log execute status of NotificationActivator::Activate

The metric is used to help investigate the issue of empty launch id
string and verify the fix to the issue of window's not becoming
foreground.

Bug:  839942 ,  837796 ,  734095 
Change-Id: Ia52d685d0b2c866aa1d048a984bf7932e5fa52f8
Reviewed-on: https://chromium-review.googlesource.com/1077369
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562725}
[modify] https://crrev.com/d326a008e79cb49bdc3871e08bf3fb8ef902b871/chrome/notification_helper/notification_activator.cc
[modify] https://crrev.com/d326a008e79cb49bdc3871e08bf3fb8ef902b871/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/d326a008e79cb49bdc3871e08bf3fb8ef902b871/tools/metrics/histograms/histograms.xml

Another update: this empty launch-id string issue only occurs during activation, so I am totally responsible for it :-)

Hopefully the CL as in comment 8 will give me more ideas. 

According to metric Notifications.NotificationHelper.NotificationActivatorSecondaryStatus, the cause of this issue is that the launch id string supplied from NotificationActivator::Activate (which is invoked by Windows) is empty!!

I checked the launch id related metrics in display, and they are almost all good. So it's highly suspicious that this is something to do with Windows.

Per the discussion with Andrew from Microsoft, the empty launch id string is generated when the app title in the Action Center is clicked. This addresses the concern that we are losing some notification related information. This bug can be closed.

As for the issue that clicking app title in the Action Center makes the toast notification disappear from AC, I will file a separate bug after more investigation.