UserAgent: Mozilla/5.0 (X11; CrOS x86_64 10718.71.2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.87 Safari/537.36
Platform: 10718.71.2 (Official Build) stable-channel guado

Example URL:
https://webrtc.github.io/samples/src/content/devices/input-output/

Steps to reproduce the problem:
1. Chrome OS 68.0.3440.87
2. Prepare at least two microphones
3. Goto open https://webrtc.github.io/samples/src/content/devices/input-output/
4. Check if all the microphones listed can work

What is the expected behavior?
all microphones listed in the dropdown list can work, we can hear the audio from speaker

What went wrong?
the Default - XXXX can work, but when we select the corresponding XXXX microphone, there is no audio heard

Did this work before? Yes 67.0.3396.99

Is it a problem with Flash or HTML5? HTML5

Does this work in other browsers? Yes

Chrome version: 68.0.3440.87  Channel: stable
OS Version: 10718.71.2
Flash Version: 30.0.0.134

Contents of chrome://gpu: 

This is critical for real-time communication applications.
 

Deleted: Screenshot 2018-08-17 at 14.31.14.png 130 KB

	Screenshot 2018-08-17 at 14.31.14.png 130 KB View Download