Incrementing VERSION to 64.0.3257.1

TBR=dimu@chromium.org

Change-Id: I9fa46157a10163cd222020b3e0176f01ed87dc0b
Reviewed-on: https://chromium-review.googlesource.com/752266
Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/branch-heads/3257@{#1}
Cr-Branched-From: 314f01c2122124dafaf99698f5049ee7d1c08140-refs/heads/master@{#513642}
1 file changed