Clear child FrameNavigationEntries if a history navigation redirects.

After the redirect, we shouldn't attempt to load the previous child
items in the new page.

BUG=585194
TBR=clamy
TEST=http/tests/navigation/back-to-redirect-with-frame.php
     in --isolate-sites-for-testing=*.is mode.
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2136873002
Cr-Commit-Position: refs/heads/master@{#405948}
7 files changed