Updating trunk VERSION from 3519.0 to 3520.0

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

Change-Id: I4cabb60493cd431bb673a5459e1283c615c6c0ec
Reviewed-on: https://chromium-review.googlesource.com/1171982Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582425}

chrome/VERSION

 MAJOR=70
 MINOR=0
-BUILD=3519
+BUILD=3520
 PATCH=0