Navigation: Move |navigation_id_| from NavigationHandleImpl to NavigationRequest.

This includes renaming it to navigation_handle_id_, which is modified
before creating NavigationHandleImpl.

Bug: 916537
Change-Id: Iea54a45c247b2c1541f56092dc461d749c27f67a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1718709
Commit-Queue: Mohamed Abdelhalim <zetamoo@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680878}
4 files changed