Remove linked_ptr from chrome/test/.

BUG=556939

Change-Id: I769c70035bc61aaf43e6e5c3494df8e725e5bde0
Reviewed-on: https://chromium-review.googlesource.com/c/1356885
Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613006}
7 files changed