Migrate empty CrcCordState to absl::NoDestructor.

Note that this only changes how we allocate the empty state, and reference countings of `empty` stay the same.

PiperOrigin-RevId: 599526339
Change-Id: I2c6aaf875c144c947e17fe8f69692b1195b55dd7

absl/crc/BUILD.bazel

@@ -182,8 +182,8 @@ cc_library(
     deps = [
         ":crc32c",
         "//absl/base:config",
+        "//absl/base:no_destructor",
         "//absl/numeric:bits",
-        "//absl/strings",
     ],
 )
 

absl/crc/CMakeLists.txt

@@ -159,6 +159,7 @@ absl_cc_library(
     absl::crc32c
     absl::config
     absl::strings
+    absl::no_destructor
 )
 
 absl_cc_test(

absl/crc/internal/crc_cord_state.cc

@@ -17,6 +17,7 @@
 #include <cassert>
 
 #include "absl/base/config.h"
+#include "absl/base/no_destructor.h"
 #include "absl/numeric/bits.h"
 
 namespace absl {
@@ -24,14 +25,14 @@ ABSL_NAMESPACE_BEGIN
 namespace crc_internal {
 
 CrcCordState::RefcountedRep* CrcCordState::RefSharedEmptyRep() {
-  static CrcCordState::RefcountedRep* empty = new CrcCordState::RefcountedRep;
+  static absl::NoDestructor<CrcCordState::RefcountedRep> empty;
 
   assert(empty->count.load(std::memory_order_relaxed) >= 1);
   assert(empty->rep.removed_prefix.length == 0);
   assert(empty->rep.prefix_crc.empty());
 
-  Ref(empty);
-  return empty;
+  Ref(empty.get());
+  return empty.get();
 }
 
 CrcCordState::CrcCordState() : refcounted_rep_(new RefcountedRep) {}