A convenience feature has been added to the latest version of the Mobile Molecular DataSheet (MMDS): the menu list for molecules now includes a Search option, which has a submenu containing both Mobile Reagents and ChemSpider:

While Mobile Reagents searching has been integrated with MMDS for quite some time, the ChemSpider search is new. It makes use of the interprocess communication feature that was added to ChemSpider Mobile app recently. Selecting it fires up the ChemSpider app, and supplies it with the current molecule, which can be used right away for searching.

If the ChemSpider Mobile app is not installed, it will helpfully direct you to the AppStore to download it for free.