Updating trunk VERSION from 3850.0 to 3851.0

# This is an automated release commit.
# Do not revert without consulting chrome-pmo@google.com.
NOAUTOREVERT=true
TBR=benmason@chromium.org

Change-Id: Ie4c9f183ab018c4739a56e699633ca17a88f8775
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1697102Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676278}

chrome/VERSION

 MAJOR=77
 MINOR=0
-BUILD=3850
+BUILD=3851
 PATCH=0