Updating trunk VERSION from 3337.0 to 3338.0

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

Change-Id: I0077afe015482b328614da282966a4886f74eebc
Reviewed-on: https://chromium-review.googlesource.com/898662Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533946}

chrome/VERSION

 MAJOR=66
 MINOR=0
-BUILD=3337
+BUILD=3338
 PATCH=0