The Ninth Circuit held that a conviction for California robbery is not a violent felony under the ACCA. A violent felony includes a crime matching the generic federal definition of extortion as well as any crime which has as an element the use, attempted use, or threatened use of physical force against a person.
First, the Court noted that some violations of the robbery statute would involve such significant levels of force as to negate any argument that the property was obtained from the owner with the owner's consent, as would be required under the generic definition of extortion.
Second, the Court noted that the accidental application of force was sufficient to sustain a robbery conviction in California, while the violent felony definition requires the intentional use of force.
Finally, the Court deemed the robbery statute to be indivisible, and therefore, not subject to a modified categorical analysis.
Given the nearly identical language of the "use of force" definition of a violent felony under the ACCA and the definition of a crime of violence under 18 USC 16(a) (used to define crime of violence aggravated felonies for immigration purposes), there is not an excellent argument to be made that robbery is not a crime of violence for immigration purposes.
In addition, the decision quotes the decision in US v. Becerril-Lopez, which (as noted in the instant decision) determined that certain conduct under California's robbery statute would match the generic definition of extortion. The generic definition of extortion requires obtaining the property with the owner's consent. A theft aggravated felony requires obtaining property without the owner's consent. Potentially (with some additional research and flushing out of the case law cited), California robbery no longer qualifies as a theft aggravated felony either.
The full text of US v. Dixon can be found here: http://cdn.ca9.uscourts.gov/datastore/opinions/2015/11/20/14-10318.pdf