leix1.wang@ Thanks for the issue.

Able to reproduce the issue on Windows 10, Mac OS 10.13.3 and Ubuntu 17.10 on the reported version 69.0.3497.100 and the latest Canary 71.0.3573.0.
Attached is the screen cast for reference.

This is a Non-Regression issue as this is observed from M-62(62.0.3196.0) chrome build, from where all the above mentioned flags are present in chrome://flags.
Hence marking this as Untriaged for further updates from Dev.

Thanks..

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According to the screencast, the sensor's not activated because there doesn't seem to be any actual sensor available ("Error message: Could not connect to a sensor"). Do the machines tested have any of the sensors that should be working?

Removing macOS and Linux flags as this issue is about Windows. As Raphael said hardware is very important here so we need to know the make and model of what this is being tested on.

Hi, I test on Dell Inspiron 13 7000 Series, this device supports the sensors. And these sensors worked on Chrome canary 71.0.3555.0~71.0.3568.0.
And the error messages on my device are：
---------------------------------------
Sensor type: Accelerometer
Frequency hint: default
Sensor activated: false
Error: NotReadableError
Error message: start() call has failed.
---------------------------------------

Thanks for the clarification, it looks like #2 was using a device without the right sensors and we all got confused. Looking at https://chromium.googlesource.com/chromium/src/+log/71.0.3568.0..71.0.3575.0?pretty=fuller&n=10000, https://chromium-review.googlesource.com/c/chromium/src/+/1246063 and https://chromium-review.googlesource.com/c/chromium/src/+/1256826 seem to be the only CLs directly related to sensors.

The former is a Windows-only CL, while the latter fixes a potential crash. I don't have any Windows laptops with sensors at hand to help bisect this though.

juncai@, which systems did you test your patch on? Can you borrow a Windows 8.1 tablet to try to reproduce this issue?

I tested the CL on my Windows 10 desktop. I will borrow a windows tablet to try to reproduce this issue.

I borrow a microsoft surface device and tested the above page:
https://intel.github.io/generic-sensor-demos/sensor-info/build/bundled/
The Canary version that I used to test is: 71.0.3577.0, and I added Accelerometer and it shows it is activated and generates sensor data.

juncai@ is currently waiting on hardware to test with.

I did some more testing using a Lenovo Thinkpad X1 Yoga laptop which has built-in sensors. I tested the page:
https://intel.github.io/generic-sensor-demos/sensor-info/build/bundled/
The Chrome versions I tested are:
Stable Version 70.0.3538.77
Canary Version 72.0.3598.0
Both versions work well and the sensors are activated and generate data.

I also tested:
Dev Version 72.0.3595.2
Beta Version 71.0.3578.30
All work well.

I test on the latest chrome canary 72.0.3598.0, the sensor doesn't work. On the same device, the sensor works well on the chrome stable. Please see the screenshot(windows8.png). My device: Dell Inspiron 13 7000 Series

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Update: I ordered a Lenove X1 Yoga machine which has Windows 10 previously installed, and hoped to install Windows 8.1 on it to reproduce this issue. But somehow the Windows 8.1 can't be installed on this machine. I will try other methods to reproduce this issue.