Do not use uninitialized Variadic.

Bug: https://crbug.com/oss-fuzz/19999
Change-Id: I979ee10418cd3ced620eca2e327f11965bd12793
diff --git a/src/trace_processor/importers/proto/proto_trace_parser.cc b/src/trace_processor/importers/proto/proto_trace_parser.cc
index 9fe74c8..08d0a98 100644
--- a/src/trace_processor/importers/proto/proto_trace_parser.cc
+++ b/src/trace_processor/importers/proto/proto_trace_parser.cc
@@ -534,6 +534,7 @@
         value = Variadic::Json(storage->InternString(metadata.json_value()));
       } else {
         context_->storage->IncrementStats(stats::empty_chrome_metadata);
+        continue;
       }
       args.AddArg(TableId::kRawEvents, row, name_id, name_id, value);
     }