Update gn files to support Mozilla build

Bug: webrtc:8670
No-Presubmit: true
Change-Id: I085dc63daa8274b5068540cbf56b6330f40643fa
Reviewed-on: https://webrtc-review.googlesource.com/38920
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21624}
diff --git a/video/BUILD.gn b/video/BUILD.gn
index 8ea959b..31ad45c 100644
--- a/video/BUILD.gn
+++ b/video/BUILD.gn
@@ -77,7 +77,6 @@
     "../call:rtp_receiver",
     "../common_video",
     "../logging:rtc_event_log_api",
-    "../media:rtc_media_base",
     "../modules:module_api",
     "../modules/bitrate_controller",
     "../modules/congestion_controller",
@@ -97,6 +96,10 @@
     "../system_wrappers",
     "../voice_engine",
   ]
+
+  if (!build_with_mozilla) {
+    deps += [ "../media:rtc_media_base" ]
+  }
 }
 
 if (rtc_include_tests) {
@@ -346,5 +349,8 @@
     if (rtc_use_h264) {
       defines += [ "WEBRTC_USE_H264" ]
     }
+    if (!build_with_mozilla) {
+      deps += [ "../media:rtc_media_base" ]
+    }
   }
 }