Add VPython checks to Chromium presubmit

These checks will validate the syntax and check that all specified packages
exist. Checks will only run when .vpython files are modified.

[email protected], [email protected]

No-Try: true
Bug: 777893
Change-Id: I57a3e2e178f2483f2b96506c11600100d932036d
Reviewed-on: https://chromium-review.googlesource.com/753342
Commit-Queue: Sergiy Byelozyorov <[email protected]>
Reviewed-by: Jochen Eisinger <[email protected]>
Cr-Commit-Position: refs/heads/master@{#514182}
1 file changed