Delete unused code in chrome/common or mark them as platform specific.

chrome/common/env_vars.cc

Index: chrome/common/env_vars.cc
diff --git a/chrome/common/env_vars.cc b/chrome/common/env_vars.cc
index 5499dc3ca8dd90ecc5f0c7b0b20d23cec45435d1..f880adbab664310ebb1b3f1914717e02d2756568 100644
--- a/chrome/common/env_vars.cc
+++ b/chrome/common/env_vars.cc
@@ -33,14 +33,4 @@ const char kRestartInfo[] = "CHROME_RESTART";
 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