Start using JniIntWrapper from Chromium instead of bypassing
it in jni_generator_helper.h.
Bug: webrtc:8278
Change-Id: I20313e1e610b05f79c210e823ab50cfb2073674e
Reviewed-on: https://webrtc-review.googlesource.com/74841
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23230}