Updating trunk VERSION from 4299.0 to 4300.0

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

Change-Id: I42c9d272577419c343a6bd08f5c2cc33f3f8631e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2491484Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#819684}

chrome/VERSION

 MAJOR=88
 MINOR=0
-BUILD=4299
+BUILD=4300
 PATCH=0