GitLab

This CL removes legacy base::Callback support from Mojo code generator,
that is no longer used.

Bug: 714018
Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I2928476e357136a7c7bbb57f83509c63fe45b321
Reviewed-on: https://chromium-review.googlesource.com/1152637Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Misha Efimov <mef@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583174}