This check verifies that all .h files in the src/ directory have an
include guard of the form

 #ifndef V8_PATH_TO_FILE_H_
 #define V8_PATH_TO_FILE_H_
 // ...
 #endif  // V8_PATH_TO_FILE_H_

The check can be skipped with a magic comment:

 // PRESUBMIT_INTENTIONALLY_MISSING_INCLUDE_GUARD

Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I0a7b96abec289ad60f64ba8418f1892a6969596d
Reviewed-on: https://chromium-review.googlesource.com/897487Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51079}