Base: Make RegistryOverrideManager support sharded/parallel tests.

chrome/installer/gcapi/gcapi_test_registry_overrider.cc

 // Copyright 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 "chrome/installer/gcapi/gcapi_test_registry_overrider.h"
 
 #include "base/guid.h"
 #include "base/strings/string16.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 
 GCAPITestRegistryOverrider::GCAPITestRegistryOverrider() {
   // Override keys - this is undone during destruction.
-  string16 hkcu_override = base::StringPrintf(
-      L"hkcu_override\\%ls", ASCIIToWide(base::GenerateGUID()));
-  override_manager_.OverrideRegistry(HKEY_CURRENT_USER, hkcu_override);
-  string16 hklm_override = base::StringPrintf(
-      L"hklm_override\\%ls", ASCIIToWide(base::GenerateGUID()));
-  override_manager_.OverrideRegistry(HKEY_LOCAL_MACHINE, hklm_override);
+  override_manager_.OverrideRegistry(HKEY_CURRENT_USER, L"hkcu_override");
+  override_manager_.OverrideRegistry(HKEY_LOCAL_MACHINE, L"hklm_override");
 }
 
 GCAPITestRegistryOverrider::~GCAPITestRegistryOverrider() {
 }