sem: Add Owner() to sem::Parameter

Change-Id: I3de1e2437b9604378b8368494363e19070443670
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/59201
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: James Price <jrprice@google.com>

src/utils/to_const_ptr_vec.h

@@ -0,0 +1,39 @@
+
+// Copyright 2021 The Tint Authors.
+//
+// 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
+//
+//     http://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.
+
+#ifndef SRC_UTILS_TO_CONST_PTR_VEC_H_
+#define SRC_UTILS_TO_CONST_PTR_VEC_H_
+
+#include <vector>
+
+namespace tint {
+namespace utils {
+
+/// @param in a vector of `T*`
+/// @returns a vector of `const T*` with the content of `in`.
+template <typename T>
+std::vector<const T*> ToConstPtrVec(const std::vector<T*>& in) {
+  std::vector<const T*> out;
+  out.reserve(in.size());
+  for (auto* ptr : in) {
+    out.emplace_back(ptr);
+  }
+  return out;
+}
+
+}  // namespace utils
+}  // namespace tint
+
+#endif  //  SRC_UTILS_TO_CONST_PTR_VEC_H_