I believe the cause is a bad include path in vm_tools.gyp

It also started show up on several chrome_informational builders. See https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/buildDetails?buildbucketId=8942453302836697728 as an example.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/023bbae3c1a7003226c25e237fd8913972e10c58

commit 023bbae3c1a7003226c25e237fd8913972e10c58
Author: Stephen Barber <smbarber@chromium.org>
Date: Thu Jun 28 20:23:47 2018

vm_tools: fix vm_tools protoc gyp path

BUG= chromium:857608 
TEST=vm_host_tools builds

Change-Id: I1bbdc6150e9c6c6a5559b7a5d066110384fd4729
Reviewed-on: https://chromium-review.googlesource.com/1119116
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Stephen Barber <smbarber@chromium.org>
Tested-by: Stephen Barber <smbarber@chromium.org>

[modify] https://crrev.com/023bbae3c1a7003226c25e237fd8913972e10c58/vm_tools/vm_tools.gyp

Tentatively fixed, I'll keep an eye on the next builds.

I can still see the failure can still be seen on some chrome_informational builders, See https://cros-goldeneye.corp.google.com/chromeos/legoland/builderSummary?builderGroups=chrome_pfq%2Cchrome_informational&limit=3&buildBranch=master

It seems to me all the informational builders that are still failing with this vm_host_tools error are amd64-* builders. Anyone has a clue? Do we need to do some special things?

bots look green to me.  please link to specific bots/logs that you still see failing.

Yes I just checked again, the amd64-* builders cycled green. I guess it just takes more time for these bots to pick up the change. Thanks.