Blink infra status: web-platform-tests sync, as of June 30

[Quinten Yearsley]

It's the end of Q2 2017! Here's where wpt sync is at the moment:

Import:

• For a little while, importer has been aborting unnecessarily to avoid clobbering exportable commits, even when there are no commits that would be clobbered (727923).
  
• To address this I made the importer also query GitHub so that it can know not to abort on account of an exportable-looking commit that has a closed PR.

Export:

• Jeff fixed a bug where the exporter wasn't filtering out all baselines from Gerrit CL patches when making PRs (730779).
  
• The next major priority for the export process is to automatically block submission of Gerrit CLs when the corresponding PR is 

Planning

• We're planning Q3 OKRs -- the overall goal is that we want to get the sync process into a low maintenance mode.