I just want to say that from a high level, 'evaluating risk' is a bad reason to add UseCounters to 1.1 APIs. The whole point of doing the origin trial in the first place was to fix this problem, so that we could change the API without worrying about usage.

We should be adding UseCounters to aid in evaluating which APIs are useful, not which are risky to change.

Risk is a general term - without these UseCounters, there is risk that we remove a useful part of the API because we assume it's not useful.  There is also app-compat risk (do we break sites).

There have been discussions for running outside of origin trial, using a new origin trial, etc.  Other browsers are going to be shipping 1.1 without a trial, so there is risk that 1.1 becomes a defacto standard that we cannot easily change in the future.

If 1.1 becomes a defacto standard then our origin trial was a huge failure. We shouldn't be at all concerned about app-compat risk at this point.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8fd773268f69e868b3f57b90708709c4b085e9cb

commit 8fd773268f69e868b3f57b90708709c4b085e9cb
Author: billorr <billorr@chromium.org>
Date: Wed Mar 15 19:56:09 2017

Add UseCounters to evaluate usage and risk with upcoming WebVR spec changes.

BUG= 701525 

Review-Url: https://codereview.chromium.org/2747803005
Cr-Commit-Position: refs/heads/master@{#457176}

[modify] https://crrev.com/8fd773268f69e868b3f57b90708709c4b085e9cb/third_party/WebKit/Source/core/frame/UseCounter.h
[modify] https://crrev.com/8fd773268f69e868b3f57b90708709c4b085e9cb/third_party/WebKit/Source/modules/vr/VRDisplay.idl
[modify] https://crrev.com/8fd773268f69e868b3f57b90708709c4b085e9cb/third_party/WebKit/Source/modules/vr/VRDisplayCapabilities.idl
[modify] https://crrev.com/8fd773268f69e868b3f57b90708709c4b085e9cb/third_party/WebKit/Source/modules/vr/VREyeParameters.idl
[modify] https://crrev.com/8fd773268f69e868b3f57b90708709c4b085e9cb/third_party/WebKit/Source/modules/vr/VRPose.idl
[modify] https://crrev.com/8fd773268f69e868b3f57b90708709c4b085e9cb/tools/metrics/histograms/histograms.xml

Requesting a merge so we can get usage metrics in 58 to drive changes in the next iteration of the origin trial.

Please add applicable OSs.  Thanks.

Your change meets the bar and is auto-approved for M58. Please go ahead and merge the CL to branch 3029 manually. Please contact milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), bhthompson@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/75ce6202acc3ef49f9c7c504c26b8f5805da97a2

commit 75ce6202acc3ef49f9c7c504c26b8f5805da97a2
Author: billorr <billorr@chromium.org>
Date: Thu Mar 16 23:27:46 2017

Add UseCounters to evaluate usage and risk with upcoming WebVR spec changes.

BUG= 701525 
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2747803005
Cr-Commit-Position: refs/heads/master@{#457176}
(cherry picked from commit 8fd773268f69e868b3f57b90708709c4b085e9cb)

Review-Url: https://codereview.chromium.org/2754783004
Cr-Commit-Position: refs/branch-heads/3029@{#250}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}

[modify] https://crrev.com/75ce6202acc3ef49f9c7c504c26b8f5805da97a2/third_party/WebKit/Source/core/frame/UseCounter.h
[modify] https://crrev.com/75ce6202acc3ef49f9c7c504c26b8f5805da97a2/third_party/WebKit/Source/modules/vr/VRDisplay.idl
[modify] https://crrev.com/75ce6202acc3ef49f9c7c504c26b8f5805da97a2/third_party/WebKit/Source/modules/vr/VRDisplayCapabilities.idl
[modify] https://crrev.com/75ce6202acc3ef49f9c7c504c26b8f5805da97a2/third_party/WebKit/Source/modules/vr/VREyeParameters.idl
[modify] https://crrev.com/75ce6202acc3ef49f9c7c504c26b8f5805da97a2/third_party/WebKit/Source/modules/vr/VRPose.idl
[modify] https://crrev.com/75ce6202acc3ef49f9c7c504c26b8f5805da97a2/tools/metrics/histograms/histograms.xml