GitLab

Expose NavigateAndCommitRendererInitiated in TestRendererHost, use it to
fix download request limiter test for renderer-initiated case in
PlzNavigate.

R=clamy@chromium.org, dominickn@chromium.org
BUG=510836

Review-Url: https://codereview.chromium.org/2319733002
Cr-Commit-Position: refs/heads/master@{#417373}