Base: Make RegistryOverrideManager support sharded/parallel tests.

chrome/installer/setup/setup_util_unittest.cc

 // Copyright (c) 2012 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 "chrome/installer/setup/setup_util_unittest.h"
 
 #include <windows.h>
 
 #include <string>
 
@@ skipping 392 matching lines @@
 
 namespace {
 
 class MigrateMultiToSingleTest : public testing::Test {
  protected:
   virtual void SetUp() OVERRIDE {
     registry_override_manager_.OverrideRegistry(kRootKey,
                                                 L"MigrateMultiToSingleTest");
   }
 
-  virtual void TearDown() OVERRIDE {
-    registry_override_manager_.RemoveAllOverrides();
-  }
-
   static const bool kSystemLevel = false;
   static const HKEY kRootKey;
   static const wchar_t kVersionString[];
   static const wchar_t kMultiChannel[];
   registry_util::RegistryOverrideManager registry_override_manager_;
 };
 
 const bool MigrateMultiToSingleTest::kSystemLevel;
 const HKEY MigrateMultiToSingleTest::kRootKey =
     kSystemLevel ? HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
@@ skipping 53 matching lines @@
                                       BrowserDistribution::CHROME_FRAME));
   EXPECT_TRUE(chrome_frame.GetUsageStats(&usagestats));
   EXPECT_EQ(1U, usagestats);
   EXPECT_EQ(L"2.0-dev", chrome_frame.channel().value());
 
   // Confirm that the binaries' channel no longer contains GCF.
   ASSERT_TRUE(binaries.Initialize(kSystemLevel,
                                   BrowserDistribution::CHROME_BINARIES));
   EXPECT_EQ(L"2.0-dev-multi", binaries.channel().value());
 }