UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.85 Safari/537.36

Steps to reproduce the problem:
DesktopCaptureDevice reduces the FPS if capturing one frame takes long time.

What is the expected behavior?
DesktopCaptureDevice should only reduce the FPS if the processor usage is way too high and may significantly impact the user experience.

What went wrong?
capturing delay != processor usage

Did this work before? No 

Chrome version: 64.0.3282.85  Channel: beta
OS Version: 
Flash Version: 

Currently only the delay of capturing is considered in DesktopCaptureDevice (https://cs.chromium.org/chromium/src/content/browser/media/capture/desktop_capture_device.cc?rcl=dd418a05cfac651906a38e9f0c570d612f20a2a8&l=397). This is not accurate, since desktop capturing is a way more complex operation then processor computing. Increasing the FPS may not impact the overall machine performance at all, but can improve the end user experience.

Julien (julien.isorce@chromium.org) composed a change (https://chromium-review.googlesource.com/c/chromium/src/+/840241) to make the FPS controllable, which I believe, is a good start for us to debug and improve the scheduling logic.