Fix more namespace stuff

test/cpp/microbenchmarks/bm_opencensus_plugin.cc

@@ -23,6 +23,7 @@
 #include "absl/base/call_once.h"
 #include "absl/strings/str_cat.h"
 #include "include/grpc++/grpc++.h"
+#include "include/grpcpp/opencensus.h"
 #include "opencensus/stats/stats.h"
 #include "src/cpp/ext/filters/census/grpc_plugin.h"
 #include "src/proto/grpc/testing/echo.grpc.pb.h"
@@ -30,7 +31,7 @@
 
 absl::once_flag once;
 void RegisterOnce() {
-  absl::call_once(once, grpc_impl::RegisterOpenCensusPlugin);
+  absl::call_once(once, grpc::RegisterOpenCensusPlugin);
 }
 
 class EchoServer final : public grpc::testing::EchoTestService::Service {
@@ -101,7 +102,7 @@ static void BM_E2eLatencyCensusEnabled(benchmark::State& state) {
   RegisterOnce();
   // This we can safely repeat, and doing so clears accumulated data to avoid
   // initialization costs varying between runs.
-  grpc_impl::RegisterOpenCensusViewsForExport();
+  grpc::RegisterOpenCensusViewsForExport();
 
   EchoServerThread server;
   std::unique_ptr<grpc::testing::EchoTestService::Stub> stub =