Rather than dropping stale navigations, resurrect the navigation entry that they were going to.

      This reverts r307614 (which drops navigations) and solves the problem with resurrection.

BUG=501515, 458361, 500576, 86758, 102408, 145969
TEST=covered by tests, as well as it shouldn't regress the original bug 86758

Review URL: https://codereview.chromium.org/1183143006

Cr-Commit-Position: refs/heads/master@{#335212}