Use a class instead of several separate globals in crash_logging.cc.

base/debug/crash_logging_unittest.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/crash_logging.h"
 
 #include <map>
 #include <string>
 
+#include "base/at_exit.h"
 #include "base/bind.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
-std::map<std::string, std::string>* key_values_ = NULL;
+std::map<std::string, std::string>* key_values_ = nullptr;
 
 }  // namespace
 
 class CrashLoggingTest : public testing::Test {
  public:
   void SetUp() override {
     key_values_ = new std::map<std::string, std::string>;
     base::debug::SetCrashKeyReportingFunctions(
         &CrashLoggingTest::SetKeyValue,
         &CrashLoggingTest::ClearKeyValue);
   }
 
   void TearDown() override {
-    base::debug::ResetCrashLoggingForTesting();
-
     delete key_values_;
-    key_values_ = NULL;
+    key_values_ = nullptr;
   }
 
  private:
   static void SetKeyValue(const base::StringPiece& key,
                           const base::StringPiece& value) {
     (*key_values_)[key.as_string()] = value.as_string();
   }
 
   static void ClearKeyValue(const base::StringPiece& key) {
     key_values_->erase(key.as_string());
   }
+
+  // The ShadowingAtExitManager will destroy the singleton used to store crash
+  // key data upon destruction.
+  base::ShadowingAtExitManager at_exit_manager_;
 };
 
 TEST_F(CrashLoggingTest, SetClearSingle) {
   const char kTestKey[] = "test-key";
   base::debug::CrashKey keys[] = { { kTestKey, 255 } };
   base::debug::InitCrashKeys(keys, arraysize(keys), 255);
 
   base::debug::SetCrashKeyValue(kTestKey, "value");
   EXPECT_EQ("value", (*key_values_)[kTestKey]);
 
@@ skipping 119 matching lines @@
   EXPECT_EQ("wor", results[2]);
   EXPECT_EQ("ld",  results[3]);
 }
 
 TEST_F(CrashLoggingTest, ChunkRounding) {
   // If max_length=12 and max_chunk_length=5, there should be 3 chunks,
   // not 2.
   base::debug::CrashKey key = { "round", 12 };
   EXPECT_EQ(3u, base::debug::InitCrashKeys(&key, 1, 5));
 }