Add observable settings for getDisplayMedia()

This CL adds observable settings to MediaStreamTrack objects returned by
getDisplayMedia() calls. These constrainable properties are set before
the stream is returned based on user choice.

Information about these settings are stored in DisplayMediaInformation
struct. It is set in the low level device selection and then parsed by
UserMediaProcessor before passing it to blink.

Bug: 326740
Change-Id: I81d5f2eb24d2c1a37df0fbe2d34bc469fa575bf1
Reviewed-by: Tom Sepez <>
Reviewed-by: Dan Sanders <>
Reviewed-by: Kentaro Hara <>
Reviewed-by: Avi Drissman <>
Reviewed-by: Guido Urdaneta <>
Reviewed-by: Weiyong Yao <>
Commit-Queue: Emircan Uysaler <>
Cr-Commit-Position: refs/heads/master@{#588162}
18 files changed