That is the only 'trusted source' I can offer you for that DL. There are various subscriptions you can use to access the DL on the MSDN site. VL is just one of them.another option Use the newest version. Get a 30 day trial to confirm the feature set is there. From what I can see reverse engineering is supported in Visio for Office 365: Want a third option?
If Visio is installed on a Windows machine you can use a software like turbo.net or cameyo.com to virtualize the app and make it portable. Hope that helps!