Small cleanups to various data types. (#8086)

- Use `bst_bin_t` in batch param constructor.
- Use `StringView` to avoid `std::string` when appropriate.
- Avoid using `MetaInfo` in quantile constructor to limit the scope of parameter.

tests/cpp/common/test_quantile.cc

@@ -82,8 +82,8 @@ void TestDistributedQuantile(size_t rows, size_t cols) {
   std::vector<float> hessian(rows, 1.0);
   auto hess = Span<float const>{hessian};
 
-  ContainerType<use_column> sketch_distributed(n_bins, m->Info(), column_size, false,
-                                               OmpGetNumThreads(0));
+  ContainerType<use_column> sketch_distributed(n_bins, m->Info().feature_types.ConstHostSpan(),
+                                               column_size, false, OmpGetNumThreads(0));
 
   if (use_column) {
     for (auto const& page : m->GetBatches<SortedCSCPage>()) {
@@ -103,8 +103,8 @@ void TestDistributedQuantile(size_t rows, size_t cols) {
   CHECK_EQ(rabit::GetWorldSize(), 1);
   std::for_each(column_size.begin(), column_size.end(), [=](auto& size) { size *= world; });
   m->Info().num_row_ = world * rows;
-  ContainerType<use_column> sketch_on_single_node(n_bins, m->Info(), column_size, false,
-                                                  OmpGetNumThreads(0));
+  ContainerType<use_column> sketch_on_single_node(n_bins, m->Info().feature_types.ConstHostSpan(),
+                                                  column_size, false, OmpGetNumThreads(0));
   m->Info().num_row_ = rows;
 
   for (auto rank = 0; rank < world; ++rank) {