Mustash: Ignore --mash flag when comparing flags in UserSessionManager.

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 ca329820e2795eeed6359c1f58f5210b6321e359..3e1b95a054faa08e65422264d89dc3c99eb1cd03 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -559,6 +559,9 @@ const char kLoadMediaRouterComponentExtension[] =
 // Makes Chrome default browser
 const char kMakeDefaultBrowser[]            = "make-default-browser";
 
+// Used to enable Mus+ash.
+const char kMash[]                          = "mash";
+
 // Forces the maximum disk space to be used by the media cache, in bytes.
 const char kMediaCacheSize[]                = "media-cache-size";