Send UpdateState when detaching a RenderFrame in FNE-enabled modes.

This ensures we do not lose PageState when navigating the main
frame, at least in the same-process navigation case.

BUG=
TEST=

Review-Url: https://codereview.chromium.org/2160523002
Cr-Commit-Position: refs/heads/master@{#406589}
2 files changed