chore: cherry-pick 229fdaf8fc05 from chromium

[nornagon]

Validate input of MediaStreamDispatcherHost::OpenDevice()

This method forwards to MediaStreamManager::OpenDevice(), which
DCHECKs for the stream type to be device video or audio capture
(i.e., webcam or mic). However, MSDH admits other stream types,
which cause MSM::OpenDevice to hit this DCHECK.

This CL ensures that a message containing an incorrect stream type,
which could be sent by a malicious renderer, results in killing the
renderer process.

Bug: 1135018
Change-Id: I3884dde95d92c41f44966a8ab1dd7bdfd4b23b9b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2472397
Auto-Submit: Guido Urdaneta guidou@chromium.org
Commit-Queue: Guido Urdaneta guidou@chromium.org
Reviewed-by: Avi Drissman avi@chromium.org
Cr-Commit-Position: refs/heads/master@{#817151}

Notes: Security: backported fix for 1135018.

[release-clerk]

Release Notes Persisted

Security: backported fix for 1135018.