Loading predictor: Allow processing of duplicate hints

Navigation predictor may send preconnect hints multiple times during
and after the page load. This CL relaxes some of the checks
in the loading predictor to allow such duplicate hints to be processed.
A duplicate hint is processed only after the first hint has completed.
Consecutive hints for the same URL would still not be processed.

Change-Id: I0101119159eead1df5c7824861d7687dc88f44c9
Bug: 919566
Reviewed-on: https://chromium-review.googlesource.com/c/1397433
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Alexandr Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621248}
4 files changed