Fix reinterpret_cast issues

It looks like these places are using incorrect casting (reinterpret_cast instead of
static_cast) for GetUserData.

BUG=

Review URL: https://codereview.chromium.org/629503004

Cr-Commit-Position: refs/heads/master@{#298743}
8 files changed