Bump the min-supported OS version in the installer.

chrome/installer/setup/setup_main.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_main.h"
 
 #include <windows.h>
 #include <msi.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 1715 matching lines @@
   installer::SetCrashKeysFromCommandLine(cmd_line);
 
   // Make sure the process exits cleanly on unexpected errors.
   base::EnableTerminationOnHeapCorruption();
   base::EnableTerminationOnOutOfMemory();
   base::win::RegisterInvalidParamHandler();
   base::win::SetupCRT(cmd_line);
 
   const bool is_uninstall = cmd_line.HasSwitch(installer::switches::kUninstall);
 
-  // Check to make sure current system is WinXP or later. If not, log
+  // Check to make sure current system is Win7 or later. If not, log
   // error message and get out.
   if (!InstallUtil::IsOSSupported()) {
-    LOG(ERROR) << "Chrome only supports Windows XP or later.";
+    LOG(ERROR) << "Chrome only supports Windows 7 or later.";

[scottmg, 2016/04/12 17:32:39]

Does setup still launch on XP even?

[grt (UTC plus 2), 2016/04/12 17:58:23]

Just tried with 50.0.2661.74, and it succeeded in laying down the new version.
My ToT component build doesn't get very far at all...

     installer_state.WriteInstallerResult(
         installer::OS_NOT_SUPPORTED, IDS_INSTALL_OS_NOT_SUPPORTED_BASE, NULL);
     return installer::OS_NOT_SUPPORTED;
   }
 
   // Initialize COM for use later.
   base::win::ScopedCOMInitializer com_initializer;
   if (!com_initializer.succeeded()) {
     installer_state.WriteInstallerResult(
         installer::OS_ERROR, IDS_INSTALL_OS_ERROR_BASE, NULL);
@@ skipping 97 matching lines @@
     // to pass through, since this is only returned on uninstall which is
     // never invoked directly by Google Update.
     return_code = InstallUtil::GetInstallReturnCode(install_status);
   }
 
   installer::EndPersistentHistogramStorage(installer_state.target_path());
   VLOG(1) << "Installation complete, returning: " << return_code;
 
   return return_code;
 }