The issue is that current navigation eviction logic allows creating loop of
navigations. This results in out-of-memory when trying to build vector of
navigations in the task in TabTasks::GetTaskIdsForNavigation().

The cause of issue is that when root navigation is evicted and later rectreated
its parent id is set to the last one seen by TabTask::UpdateWithNavigation.

The solution is to remember which navigation was created first (root navigation)
and to exclude it from eviction logic.

BUG=766963
R=zea@chromium.org

Change-Id: If994721f67050771e8a9555c3399b0d252e39596
Reviewed-on: https://chromium-review.googlesource.com/710474


Commit-Queue: Pavel Yatsuk <pavely@chromium.org>
Reviewed-by: Nicolas Zea <zea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508032}