Support rollback with installerdata in mini_installer

chrome/installer/setup/setup_util.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.
 //
 // This file declares util functions for setup project.
 
 #include "chrome/installer/setup/setup_util.h"
 
 #include <windows.h>
 #include <stddef.h>
 
 #include <algorithm>
 #include <iterator>
 #include <set>
+#include <string>
 
 #include "base/command_line.h"
 #include "base/cpu.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/version.h"
 #include "base/win/registry.h"
 #include "base/win/windows_version.h"
 #include "chrome/installer/setup/setup_constants.h"
 #include "chrome/installer/util/app_registration_data.h"
 #include "chrome/installer/util/google_update_constants.h"
 #include "chrome/installer/util/installation_state.h"
 #include "chrome/installer/util/installer_state.h"
+#include "chrome/installer/util/master_preferences.h"
+#include "chrome/installer/util/master_preferences_constants.h"
 #include "chrome/installer/util/util_constants.h"
 #include "courgette/courgette.h"
 #include "courgette/third_party/bsdiff.h"
 #include "third_party/bspatch/mbspatch.h"
 
 namespace installer {
 
 namespace {
 
 // Returns true if product |type| cam be meaningfully installed without the
@@ skipping 489 matching lines @@
   std::reverse_copy(input + 21, input + 23, output);
   std::reverse_copy(input + 24, input + 26, output);
   std::reverse_copy(input + 26, input + 28, output);
   std::reverse_copy(input + 28, input + 30, output);
   std::reverse_copy(input + 30, input + 32, output);
   std::reverse_copy(input + 32, input + 34, output);
   std::reverse_copy(input + 34, input + 36, output);
   return squid;
 }
 
+bool IsDowngradeAllowed(const MasterPreferences& prefs) {
+  bool allow_downgrade = false;
+  return prefs.GetBool(master_preferences::kAllowDowngrade, &allow_downgrade) &&
+         allow_downgrade;
+}
+
 ScopedTokenPrivilege::ScopedTokenPrivilege(const wchar_t* privilege_name)
     : is_enabled_(false) {
   HANDLE temp_handle;
   if (!::OpenProcessToken(::GetCurrentProcess(),
                           TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY,
                           &temp_handle)) {
     return;
   }
   token_.Set(temp_handle);
 
@@ skipping 22 matching lines @@
 }
 
 ScopedTokenPrivilege::~ScopedTokenPrivilege() {
   if (is_enabled_ && previous_privileges_.PrivilegeCount != 0) {
     ::AdjustTokenPrivileges(token_.Get(), FALSE, &previous_privileges_,
                             sizeof(TOKEN_PRIVILEGES), NULL, NULL);
   }
 }
 
 }  // namespace installer