The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fc3961b8fc2138c497210bc69e6d4321eebad599

commit fc3961b8fc2138c497210bc69e6d4321eebad599
Author: jialiul <jialiul@chromium.org>
Date: Wed Jul 20 02:31:13 2016

Add UMA to record why chrome shows generic warning

Since DownloadProtectionService started to return "UNKOWN" verdict for
some types, we need a UMA metrics to track how many generic warnings
(Dangerous file warnings) are caused by these UNKOWN verdicts,
vs. caused by SAFE verdicts for some types, or the unavailability of SB
service.

BUG= 627244 

Review-Url: https://codereview.chromium.org/2160003002
Cr-Commit-Position: refs/heads/master@{#406468}

[modify] https://crrev.com/fc3961b8fc2138c497210bc69e6d4321eebad599/chrome/browser/download/chrome_download_manager_delegate.cc
[modify] https://crrev.com/fc3961b8fc2138c497210bc69e6d4321eebad599/tools/metrics/histograms/histograms.xml

Safe Browsing Bineval team needs this metrics to decide how to handle safe browsing verdicts of dmg, xml and other types. 
Due to its security implication, request merge into M52 stable. 

Already started to receiving data from Canary, everything looks fine. Thanks! 

[Automated comment] Request affecting a post-stable build (M52), manual review required.

Is this change applicable to all OS or any specific OS?

It is applicable to all desktop version. Thanks!

OK, thank you.

Based on updater #5, everything looks good in canary which is good.
As M52 is already in Stable for Desktop, bar is VERY high. We're going to have M52 refresh Stable release next week and we can take this change in ONLY if it is critical, well baked and very safe to merge. Please confirm this. 

Confirm this change is critical (since it is safe browsing related) and safe to merge (since it only adds UMA metric). Thanks!

Approving merge to M52 branch 2743 based on comment #5 and comment #10. Please merge ASAP. Thank you.

Also is this require a merge to M53? If yes, please request a merge.

Your change meets the bar and is auto-approved for M53 (branch: 2785)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f117e624f510065d5ced27b3bb67b8a22c5c4d08

commit f117e624f510065d5ced27b3bb67b8a22c5c4d08
Author: Jialiu Lin <jialiul@chromium.org>
Date: Thu Jul 28 22:25:02 2016

Add UMA to record why chrome shows generic warning

Since DownloadProtectionService started to return "UNKOWN" verdict for
some types, we need a UMA metrics to track how many generic warnings
(Dangerous file warnings) are caused by these UNKOWN verdicts,
vs. caused by SAFE verdicts for some types, or the unavailability of SB
service.

BUG= 627244 

Review-Url: https://codereview.chromium.org/2160003002
Cr-Commit-Position: refs/heads/master@{#406468}
(cherry picked from commit fc3961b8fc2138c497210bc69e6d4321eebad599)

Review URL: https://codereview.chromium.org/2194603002 .

Cr-Commit-Position: refs/branch-heads/2743@{#707}
Cr-Branched-From: 2b3ae3b8090361f8af5a611712fc1a5ab2de53cb-refs/heads/master@{#394939}

[modify] https://crrev.com/f117e624f510065d5ced27b3bb67b8a22c5c4d08/chrome/browser/download/chrome_download_manager_delegate.cc
[modify] https://crrev.com/f117e624f510065d5ced27b3bb67b8a22c5c4d08/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/088341166e56e7d953c2653d09d48de6792bf409

commit 088341166e56e7d953c2653d09d48de6792bf409
Author: Jialiu Lin <jialiul@chromium.org>
Date: Thu Jul 28 22:29:09 2016

Add UMA to record why chrome shows generic warning

Since DownloadProtectionService started to return "UNKOWN" verdict for
some types, we need a UMA metrics to track how many generic warnings
(Dangerous file warnings) are caused by these UNKOWN verdicts,
vs. caused by SAFE verdicts for some types, or the unavailability of SB
service.

BUG= 627244 

Review-Url: https://codereview.chromium.org/2160003002
Cr-Commit-Position: refs/heads/master@{#406468}
(cherry picked from commit fc3961b8fc2138c497210bc69e6d4321eebad599)

Review URL: https://codereview.chromium.org/2195483002 .

Cr-Commit-Position: refs/branch-heads/2785@{#397}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}

[modify] https://crrev.com/088341166e56e7d953c2653d09d48de6792bf409/chrome/browser/download/chrome_download_manager_delegate.cc
[modify] https://crrev.com/088341166e56e7d953c2653d09d48de6792bf409/tools/metrics/histograms/histograms.xml