Reland "Add multiplex case to webrtc_perf_tests"

This is a reland of d90a7e842437f5760a34bbfa283b3c4182963889

Original change's description:
> Add multiplex case to webrtc_perf_tests
>
> This CL adds two new tests to perf, covering I420 and I420A input to multiplex
> codec. In order to have the correct input, it adds I420A case to
> SquareGenerator and corresponding PSNR and SSIM calculations.
>
> Bug: webrtc:7671
> Change-Id: I9735d725bbfba457e804e29907cee55406ae5c8d
> Reviewed-on: https://webrtc-review.googlesource.com/52180
> Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
> Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
> Reviewed-by: Erik Språng <sprang@webrtc.org>
> Commit-Queue: Emircan Uysaler <emircan@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#22330}

Bug: webrtc:7671
Change-Id: Ib6e37ce4bc0bae903dd72f49ffdc2ee583d75491
TBR: niklas.enbom@webrtc.org, phoglund@webrtc.org, sprang@webrtc.org
Reviewed-on: https://webrtc-review.googlesource.com/61120
Reviewed-by: Emircan Uysaler <emircan@webrtc.org>
Commit-Queue: Emircan Uysaler <emircan@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22376}
diff --git a/test/DEPS b/test/DEPS
index d55be1b..f3dbff1 100644
--- a/test/DEPS
+++ b/test/DEPS
@@ -6,6 +6,7 @@
   "+common_video",
   "+logging/rtc_event_log",
   "+media/base",
+  "+media/engine",
   "+modules/audio_coding",
   "+modules/audio_device",
   "+modules/audio_mixer",