[spelling] existance to existence

chrome/installer/util/scoped_user_protocol_entry.h

Index: chrome/installer/util/scoped_user_protocol_entry.h
diff --git a/chrome/installer/util/scoped_user_protocol_entry.h b/chrome/installer/util/scoped_user_protocol_entry.h
index eee58d2b9e5bd844630dfe0a681f05c064d632a5..85ad2d9c99a643702852e012c3b3b9bd348d36d8 100644
--- a/chrome/installer/util/scoped_user_protocol_entry.h
+++ b/chrome/installer/util/scoped_user_protocol_entry.h
@@ -15,7 +15,7 @@ class RegistryEntry;
 // Windows 8 shows the "No apps are installed to open this type of link"
 // dialog when choosing a default handler for a |protocol| under certain
 // circumstances. Under these circumstances, it appears that ensuring the
-// existance of the HKCU\Software\Classes\<protocol> key with an empty "URL
+// existence of the HKCU\Software\Classes\<protocol> key with an empty "URL
 // Protocol" value is sufficient to make the dialog contain the usual list of
 // registered browsers. This class creates this key and value in its constructor
 // if needed, and cleans them up in its destructor if no other values or subkeys