Updating trunk VERSION from 3388.0 to 3389.0

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

Change-Id: I81d05739dd71d1ae126ad695713e1024e1899e03
Reviewed-on: https://chromium-review.googlesource.com/994674Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547959}

chrome/VERSION

 MAJOR=67
 MINOR=0
-BUILD=3388
+BUILD=3389
 PATCH=0