Since this is a def, it will instantiate a new empty cache on every access, so you will get 0 cache hits.  It should be a val.

Also, I'm not sure that we need an evictable cache here.  This cache holds info about assets, `AssetInfo` looks like it will be about 200 bytes in size, a big project might have 1000 assets, that's only 200kb of meta data to store.  Even if we do want it to be evictable, the size here needs to be configurable, if you did have a project with many assets, and these assets were all used very frequently, then sprays default maximum size (500) may cause big performance problems.

Also, not sure that we should be using spray cache here - I think it's going away, I don't think they are migrating it to Akka.  Since it's not being maintained anymore, it means for example we're not likely to get a Scala 2.11 build of it, which will prevent Play 2.3 from running with Scala 2.11.  It also brings in a dependency on guava, which we've been trying to avoid in play-core.