Clone children of FrameNavigationEntries for in-page navigations.

BUG=623681, 522193, 561034
TEST=See bug for repro steps
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2161393002
Cr-Commit-Position: refs/heads/master@{#407832}
7 files changed