This should do the same things as the stand-alone gyp build, but with gn.
You should switch to gn as gyp support will go away.

You need a recent enough version of gn.  If yours is too old try this one:
  ./buildtools/linux64/gn

If "gclient sync" or anything fails with an ImportError on gyp stuff,
try running it with the following PYTHONPATH in the environment:
  PYTHONPATH=tools/gyp/pylib

BUG=angleproject:1569

Change-Id: I56d19bec2d8b649a7bd65062c656cbfc69ea3dd8
Reviewed-on: https://chromium-review.googlesource.com/642588Reviewed-by: Frank Henigman <fjhenigman@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>