Remove redundant uint64_t typedef

This was created by this refactoring patch:
https://codereview.chromium.org/1538743002

R=avi@chromium.org, mark@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2123973003
Cr-Commit-Position: refs/heads/master@{#404201}
1 file changed