UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36

Example URL:
https://webrtc.github.io/samples/src/content/peerconnection/constraints/

Steps to reproduce the problem:
1. use the demo  https://webrtc.github.io/samples/src/content/peerconnection/constraints/   to getusermedia with constraints : 
video:{
width :{max:1920,min:1920} , height:{max:1080,min:1080},frameRate:{max:15,min:15}
}
to open 1080P camera: Microsoft LifeCam Studio   in windows

What is the expected behavior?
the framerate should be almost 15fps

What went wrong?
the framerate is 6 or 7 fps , but the demo works well(framerate is almost 15fps) in MacOS using chrome.

Did this work before? N/A 

Is it a problem with Flash or HTML5? N/A

Does this work in other browsers? N/A

Chrome version: 62.0.3202.94  Channel: n/a
OS Version: 10.0
Flash Version: 

Contents of chrome://gpu: