[base] Provide ITypedEventHandler Implementation

This change provides an implementation of Windows::Foundation's
ITypedEventHandlder. It serves as a thin wrapper around a
base::RepeatingCallback of the appropriate signature.

Bug: 821766
Change-Id: Ib940ebc5a4d90e5304be2c08839efbc020011180
Reviewed-on: https://chromium-review.googlesource.com/1060054
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559212}
3 files changed