Canon Rumors has gotten ahold of the official promo video for the upcoming Canon 90D. The video was leaked just minutes ago, and it reveals all of the key specs and design elements for what may be Canon’s new flagship APS-C DSLR. Previous rumors indicated that the EOS 90D would replace both the Canon 80D and the Canon 7D Mark II, making it Canon’s new APS-C flagship DSLR. While it doesn’t seem that the upcoming 90D will totally fill the…