dojox.mobile.createDomButton could cause a script error

[ykami]

In createDomButton, the following code exists.

var rules = sheet.cssRules;

In some situations, this could be null. Therefore it has to be

var rules = sheet.cssRules || [];

reported by Doug

[ykami]

In [26895]:

Fixes #14138 !strict. Added "

[]" to sheet.cssRules for safety following Doug's suggestion. Apparently the fix is safe and does nothing harmful. Thanks Doug for the suggestion.