Fix system-level detection in the mini_installer.

chrome/installer/mini_installer/configuration.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/mini_installer/configuration.h"
 
+#include <windows.h>
 #include <shellapi.h>  // NOLINT
 #include <stddef.h>
 
 #include "chrome/installer/mini_installer/appid.h"
 #include "chrome/installer/mini_installer/mini_installer_constants.h"
 #include "chrome/installer/mini_installer/mini_installer_resource.h"
 #include "chrome/installer/mini_installer/regkey.h"
 
 namespace mini_installer {
 
+namespace {
+
+// Returns true if GoogleUpdateIsMachine=1 is present in the environment.
+bool GetGoogleUpdateIsMachineEnvVar() {
+  const DWORD kBufferSize = 2;
+  StackString<kBufferSize> value;
+  DWORD length = ::GetEnvironmentVariableW(L"GoogleUpdateIsMachine",
+                                           value.get(), kBufferSize);
+  return length == 1 && *value.get() == L'1';
+}
+
+}  // namespace
+
 Configuration::Configuration() : args_(NULL) {
   Clear();
 }
 
 Configuration::~Configuration() {
   Clear();
 }
 
 // When multi_install is true, we are potentially:
 // 1. Performing a multi-install of some product(s) on a clean machine.
@@ skipping 89 matching lines @@
       else if (0 == ::lstrcmpi(args_[i], L"--chrome-frame"))
         has_chrome_frame_ = true;
       else if (0 == ::lstrcmpi(args_[i], L"--multi-install"))
         is_multi_install_ = true;
       else if (0 == ::lstrcmpi(args_[i], L"--system-level"))
         is_system_level_ = true;
       else if (0 == ::lstrcmpi(args_[i], L"--cleanup"))
         operation_ = CLEANUP;
     }
 
+    if (!is_system_level_)
+      is_system_level_ = GetGoogleUpdateIsMachineEnvVar();
     SetChromeAppGuid();
     if (!is_multi_install_) {
       has_chrome_ = !has_chrome_frame_;
     }
   }
 
   return args_ != NULL;
 }
 
 void Configuration::ReadResources(HMODULE module) {
@@ skipping 19 matching lines @@
   size_t version_len = version_size / sizeof(wchar_t);
 
   // The string must be terminated.
   if (version_string[version_len - 1])
     return;
 
   previous_version_ = version_string;
 }
 
 }  // namespace mini_installer