Updating trunk VERSION from 3430.0 to 3431.0

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

Change-Id: I0950d5fe5966d56308402c65300e6466bb32f0eb
Reviewed-on: https://chromium-review.googlesource.com/1056022Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558183}

chrome/VERSION

 MAJOR=68
 MINOR=0
-BUILD=3430
+BUILD=3431
 PATCH=0