Navigation: Remove unused includes and members.

Remove unused includes and members from NavigationHandleImpl.

Change-Id: I8aca71e2d8044623ca88c9c166616d31172e357c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1505436
Reviewed-by: Camille Lamy <clamy@chromium.org>
Commit-Queue: Mohamed Abdelhalim <zetamoo@google.com>
Cr-Commit-Position: refs/heads/master@{#638559}
2 files changed