Support --delete-old-versions in setup.exe.

chrome/installer/setup/setup_singleton.cc

 // Copyright 2016 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_singleton.h"
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 74 matching lines @@
   installer_state->Initialize(command_line, master_preferences,
                               *original_state);
 
   RecordSetupSingletonAcquisitionResultHistogram(
       SETUP_SINGLETON_ACQUISITION_SUCCESS);
   return setup_singleton;
 }
 
 SetupSingleton::~SetupSingleton() = default;
 
-bool SetupSingleton::WaitForInterrupt(const base::TimeDelta& max_time) {
+bool SetupSingleton::WaitForInterrupt(const base::TimeDelta& max_time) const {
   const bool exit_event_signaled = exit_event_.TimedWait(max_time);
   return exit_event_signaled;
 }
 
 SetupSingleton::ScopedHoldMutex::ScopedHoldMutex() = default;
 
 SetupSingleton::ScopedHoldMutex::~ScopedHoldMutex() {
   if (mutex_ != INVALID_HANDLE_VALUE)
     ::ReleaseMutex(mutex_);
 }
@@ skipping 23 matching lines @@
       exit_event_(base::win::ScopedHandle(::CreateEvent(
           nullptr,
           TRUE,
           FALSE,
           (L"Global\\ChromeSetupExitEvent_" + sync_primitive_name_suffix)
               .c_str()))) {
   DCHECK(setup_mutex_.IsValid());
 }
 
 }  // namespace installer