Convert Uses of base::RepeatingCallback<>::Equals to Use == or != in //base

Staging this change because some conversions will have semantic changes.

BUG=937566

Change-Id: I2d4950624c0fab00e107814421a161e43da965cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1507245
Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639702}
  void TheMethod() {}

  void TheMethod() {}
