Resolve media/cast crypto crash, and add crash reporting.

media/cast/net/cast_transport_sender_impl.cc

Index: media/cast/net/cast_transport_sender_impl.cc
diff --git a/media/cast/net/cast_transport_sender_impl.cc b/media/cast/net/cast_transport_sender_impl.cc
index c3afc276b335c030f2140a68ea0be9857e418afe..9a763de21c3772738f4ed0d3346212279908d409 100644
--- a/media/cast/net/cast_transport_sender_impl.cc
+++ b/media/cast/net/cast_transport_sender_impl.cc
@@ -242,7 +242,9 @@ namespace {
 void EncryptAndSendFrame(const EncodedFrame& frame,
                          TransportEncryptionHandler* encryptor,
                          RtpSender* sender) {
-  if (encryptor->is_activated()) {
+  // TODO(miu): We probably shouldn't attempt to send an empty frame, but this
+  // issue is still under investigation.  http://crbug.com/519022
+  if (encryptor->is_activated() && !frame.data.empty()) {
     EncodedFrame encrypted_frame;
     frame.CopyMetadataTo(&encrypted_frame);
     if (encryptor->Encrypt(frame.frame_id, frame.data, &encrypted_frame.data)) {