Delete deprecated constructor of SendSideCongestionController.

Move packet_router #include to where it's needed, and delete unused
MockPacketRouter.

Bug: webrtc:6847
Change-Id: I03c86c6fb8b413f5a535a237fa1724cc10960ffa
Reviewed-on: https://webrtc-review.googlesource.com/17320
Commit-Queue: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20564}
diff --git a/rtc_tools/BUILD.gn b/rtc_tools/BUILD.gn
index ef62b1f..59ee4ea 100644
--- a/rtc_tools/BUILD.gn
+++ b/rtc_tools/BUILD.gn
@@ -223,6 +223,7 @@
         # TODO(kwiberg): Remove this dependency.
         "../api/audio_codecs:audio_codecs_api",
         "../modules/congestion_controller",
+        "../modules/pacing",
         "../modules/rtp_rtcp",
         "../system_wrappers:system_wrappers_default",
         "//build/config:exe_and_shlib_deps",