Sync verification state.

// FREEBIE

protobuf/OWSSignalServiceProtos.proto

@@ -124,12 +124,27 @@ message SyncMessage {
     optional uint64 timestamp = 2;
   }
 
+  message Verification {
+    enum State {
+      DEFAULT            = 0;
+      VERIFIED           = 1;
+      NO_LONGER_VERIFIED = 2;
+    }
+
+    optional State  state       = 1;
+    // The e164 phone number of the user.
+    optional string destination = 2;
+    // identityKey should be set IFF state is VERIFIED.
+    optional bytes  identityKey = 3;
+  }
+
   optional Sent     sent             = 1;
   optional Contacts contacts         = 2;
   optional Groups   groups           = 3;
   optional Request  request          = 4;
   repeated Read     read             = 5;
   optional Blocked  blocked          = 6;
+  repeated Verification verification = 7;
 }
 
 message AttachmentPointer {