NQE: clean up constructor

NQE (Network Quality Estimator): Remove args from NQE constructor
that are only used by tests.

Bug: 696142
Change-Id: Idda7375d433f7d76e3b8857421b7baa75220fa8f
Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester
Reviewed-on: https://chromium-review.googlesource.com/581612
Commit-Queue: Tarun Bansal <[email protected]>
Reviewed-by: Ryan Sturm <[email protected]>
Cr-Commit-Position: refs/heads/master@{#489083}
7 files changed