Move ComputeFoundation to Candidate.

Move code from P2PTransportChannel to Candidate, where we set the
foundation value for remote prflx candidates.

Bug: none
Change-Id: I7dbcb85bca35dca7297136b0706092dd8d2b153c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/339902
Reviewed-by: Philipp Hancke <phancke@microsoft.com>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41774}
diff --git a/api/BUILD.gn b/api/BUILD.gn
index 0c982a2..9ced1f2 100644
--- a/api/BUILD.gn
+++ b/api/BUILD.gn
@@ -183,7 +183,9 @@
     "candidate.h",
   ]
   deps = [
+    "../p2p:p2p_constants",
     "../rtc_base:checks",
+    "../rtc_base:crc32",
     "../rtc_base:ip_address",
     "../rtc_base:logging",
     "../rtc_base:network_constants",