tree db2a7688fc0f565aefbee9c55966dda96ffd5460
parent 783a5f6bb3d2a11e5923fbd7fc47ec89dcc1824c
author Natalie Weizenbaum <nweiz@google.com> 1460493733 -0700
committer Natalie Weizenbaum <nweiz@google.com> 1460493733 -0700

Add typed wrapper functions to delegate classes.

These mirror the methods in the the collection package, and serve a
similar purpose of safely casting generic objects when the user is
confident that the actual object's values are more specific than the
static type.

R=floitsch@google.com, lrn@google.com

Review URL: https://codereview.chromium.org//1870543004 .