GitLab

Add a function to convert the response from a test results request
into a data frame for convenient access of the data.

Also add corresponding unit tests.

Bug: 875251
Change-Id: I396a5c209e37a470ab305edbee82ccc407472766
Reviewed-on: https://chromium-review.googlesource.com/1185184Reviewed-by: Ned Nguyen <nednguyen@google.com>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585525}