Introduce api/crypto/BUILD.gn.

No-Try: True
Bug: webrtc:8733
Change-Id: I8679735be1e5069e371a9f1115a54e897e09964b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/152622
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29186}
diff --git a/BUILD.gn b/BUILD.gn
index 9207a1d..baedb39 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -400,7 +400,9 @@
     deps = [
       ":webrtc_common",
       "api:libjingle_peerconnection_api",
+      "api:rtc_error",
       "api:transport_api",
+      "api/crypto",
       "api/rtc_event_log:rtc_event_log_factory",
       "audio",
       "call",