Create definition point for kNsdTypeInfo.

Per the standard, this is necessary since the variable is ODR-used, though some compilers will not complain without it because ODR violations do not require a diagnostic.

PiperOrigin-RevId: 406741338

cpp/platform/base/BUILD

@@ -21,6 +21,7 @@ cc_library(
         "base64_utils.cc",
         "bluetooth_utils.cc",
         "input_stream.cc",
+        "nsd_service_info.cc",
         "prng.cc",
     ],
     hdrs = [

cpp/platform/base/nsd_service_info.cc

@@ -0,0 +1,23 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "platform/base/nsd_service_info.h"
+
+namespace location {
+namespace nearby {
+
+constexpr absl::string_view NsdServiceInfo::kNsdTypeFormat;
+
+}  // namespace nearby
+}  // namespace location