Fixing //content/renderer deps on WebRTC.

WebRTC is moving away from public_deps and CL
https://webrtc-review.googlesource.com/c/src/+/33180 will remove them
from the //third_party/webrtc/media package.

This CL applies a forward compatible fix to avoid to break Chromium.

Bug: webrtc:8603
Change-Id: I89a4421362a9451633de2b23fd9ed3fd57ecf0cd
No-Try: True
Reviewed-on: https://chromium-review.googlesource.com/829139
Commit-Queue: Mirko Bonadei <mbonadei@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524369}

content/renderer/BUILD.gn

@@ -940,6 +940,7 @@ target(link_target_type, "renderer") {
       "//third_party/webrtc/api/audio_codecs/opus:audio_encoder_opus",
       "//third_party/webrtc/api/video_codecs:video_codecs_api",
       "//third_party/webrtc/common_video:common_video",
+      "//third_party/webrtc/media:rtc_audio_video",
       "//third_party/webrtc/media:rtc_media",
       "//third_party/webrtc/media:rtc_media_base",
       "//third_party/webrtc/modules/audio_device",