Updating trunk VERSION from 3428.0 to 3429.0

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

Change-Id: I8edc2fffd92bf1fa4ec493ea760bab8fe5fe94ce
Reviewed-on: https://chromium-review.googlesource.com/1056113Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558101}

chrome/VERSION

 MAJOR=68
 MINOR=0
-BUILD=3428
+BUILD=3429
 PATCH=0