Don't accidentally propagate Omaha variable to child processes.

chrome/common/env_vars.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/common/env_vars.h"
 
 namespace env_vars {
 
 // We call running in unattended mode (for automated testing) "headless".
 // This mode can be enabled using this variable or by the kNoErrorDialogs
@@ skipping 14 matching lines @@
 
 // The strings RIGHT_TO_LEFT and LEFT_TO_RIGHT indicate the locale direction.
 // For example, for Hebrew and Arabic locales, we use RIGHT_TO_LEFT so that the
 // dialog is displayed using the right orientation.
 const char kRtlLocale[] = "RIGHT_TO_LEFT";
 const char kLtrLocale[] = "LEFT_TO_RIGHT";
 
 // Number of times to run a given startup_tests unit test.
 const char kStartupTestsNumCycles[] = "STARTUP_TESTS_NUMCYCLES";
 
+// The presence of this environment variable with a value of 1 implies that
+// setup.exe should run as a system installation regardless of what is on the
+// command line.
+// TODO(erikwright): Put this in chrome/installer/util/util_constants.cc when
+// http://crbug.com/174953 is fixed and widely deployed.
+const char kGoogleUpdateIsMachineEnvVar[] = "GoogleUpdateIsMachine";
+
 }  // namespace env_vars