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

chrome/common/crash_keys_unittest.cc

Index: chrome/common/crash_keys_unittest.cc
diff --git a/chrome/common/crash_keys_unittest.cc b/chrome/common/crash_keys_unittest.cc
index 5dd04b2235b2405097558cb44eafc6d74b73b3c1..959d6332109dc049cc386e46db902de528fe8bd7 100644
--- a/chrome/common/crash_keys_unittest.cc
+++ b/chrome/common/crash_keys_unittest.cc
@@ -8,6 +8,7 @@
 #include <set>
 #include <string>
 
+#include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/debug/crash_logging.h"
@@ -25,7 +26,6 @@ class CrashKeysTest : public testing::Test {
   }
 
   void TearDown() override {
-    base::debug::ResetCrashLoggingForTesting();
     self_ = NULL;
   }
 
@@ -53,6 +53,10 @@ class CrashKeysTest : public testing::Test {
   static CrashKeysTest* self_;
 
   std::map<std::string, std::string> keys_;
+
+  // The ShadowingAtExitManager will destroy the singleton used to store crash
+  // key data upon destruction.
+  base::ShadowingAtExitManager at_exit_manager_;
 };
 
 CrashKeysTest* CrashKeysTest::self_ = NULL;