Fix compile failure with GCC 4.5.0 (issue 1244)
Fix compile failure with GCC 4.5.0 (issue 1244)

GCC apparently assumes that given that we do a static cast in the next
line the value must actually be in StrictModeFlag enum range (even
though this is actually what we are asserting)


Review URL: http://codereview.chromium.org/6670031

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@7147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh