Add a type param to goog.events.EventHandler<any>
Add a type param to goog.structs.Map<any, any>
Add type params to generic classes.

- goog.Promise
- goog.iter.Iterator
- goog.structs.Heap
- goog.structs.Pool
- goog.structs.PriorityPool
- goog.structs.Set
- goog.structs.TreeNode