change PacketBuffer to return it's result rather that use callback

Bug: None
Change-Id: I8cc05dd46e811d6db37af520d2106af21c671def
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/157893
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29589}
diff --git a/modules/video_coding/BUILD.gn b/modules/video_coding/BUILD.gn
index cd17c66..c14186b 100644
--- a/modules/video_coding/BUILD.gn
+++ b/modules/video_coding/BUILD.gn
@@ -84,6 +84,7 @@
     "../../system_wrappers:field_trial",
     "../../system_wrappers:metrics",
     "../rtp_rtcp:rtp_video_header",
+    "//third_party/abseil-cpp/absl/base:core_headers",
     "//third_party/abseil-cpp/absl/memory",
   ]