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/sdk/BUILD.gn b/sdk/BUILD.gn
index 125c6cb..6fa4971 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -927,6 +927,8 @@
         "../api/audio_codecs:audio_codecs_api",
         "../api/audio_codecs:builtin_audio_decoder_factory",
         "../api/audio_codecs:builtin_audio_encoder_factory",
+        "../api/crypto:frame_decryptor_interface",
+        "../api/crypto:frame_encryptor_interface",
         "../api/rtc_event_log:rtc_event_log_factory",
         "../api/task_queue:default_task_queue_factory",
         "../api/transport/media:media_transport_interface",