[Mac] Adds a flag to force 10.6-style fullscreen for testing.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 36a2ece17ff878eb2d094ef8bccb4f60d9d9024b..a6c4cf079a74cc7297dd46f0aed662b97386d9b7 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -1482,6 +1482,11 @@ const char kPasswordStore[]                 = "password-store";
 #endif  // OS_POSIX
 
 #if defined(OS_MACOSX)
+// Forcibly disables Lion-style on newer OSes, to allow developers to test the
+// older, SnowLeopard-style fullscreen.
+const char kDisableSystemFullscreenForTesting[] =
+    "disable-system-fullscreen-for-testing";
+
 // Enables the app list OSX .app shim, for showing the app list. If the flag is
 // not present, Chrome will check if the shim exists at startup, and delete it
 // if it does.