Base: Make RegistryOverrideManager support sharded/parallel tests.

chrome/installer/util/product_state_unittest.cc

 // Copyright (c) 2011 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 <windows.h>
 
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_reg_util_win.h"
 #include "base/version.h"
 #include "base/win/registry.h"
@@ skipping 77 matching lines @@
 }
 
 void ProductStateTest::TearDown() {
   // Done with the keys.
   client_state_.Close();
   clients_.Close();
   EXPECT_EQ(ERROR_SUCCESS, ::RegOverridePredefKey(overridden_, NULL));
   overridden_ = NULL;
   system_install_ = false;
 
-  // Shotgun approach to clearing out data we may have written.
-  RegistryOverrideManager::DeleteAllTempKeys();
-
   testing::Test::TearDown();
 }
 
 void ProductStateTest::MinimallyInstallProduct(const wchar_t* version) {
   EXPECT_EQ(ERROR_SUCCESS,
             clients_.WriteValue(google_update::kRegVersionField, version));
 }
 
 void ProductStateTest::ApplyUninstallCommand(const wchar_t* exe_path,
                                              const wchar_t* args) {
@@ skipping 308 matching lines @@
 
   // Uninstall command with --multi-install is multi install.
   {
     ProductState state;
     ApplyUninstallCommand(L"setup.exe",
                           L"--uninstall --chrome --multi-install");
     EXPECT_TRUE(state.Initialize(system_install_, dist_));
     EXPECT_TRUE(state.is_multi_install());
   }
 }