Parameterize PeerConnection media tests for Unified Plan

Bug: webrtc:8765
Change-Id: I9bcd053c3e5f6524576f8da9f818de82fcd1836d
Reviewed-on: https://webrtc-review.googlesource.com/41020
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21754}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index c665e03..10c7388 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -832,6 +832,7 @@
     "fakesslidentity.h",
     "firewallsocketserver.cc",
     "firewallsocketserver.h",
+    "gunit.cc",
     "gunit.h",
     "httpbase.cc",
     "httpbase.h",