GitLab

- Maintains a mapping of fake methods, resolvers and fake data

Bug: 1125150
Test: browser_tests --gtest_filter=DiagnosticsApp*
Change-Id: Ic07ddfc300679611b4d8dc908bb61a30631e9874
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417450
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Reviewed-by: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808543}