gl_tests: Use zero size gl surface for offscreen rendering

In GLX, most of the drivers can cope with both PBuffer and Surfaceless modes
for offscreen rendering. In EGL though, Intel driver only works with
Surfaceless.

This CL changes all hardware platforms to use Surfaceless by forcing a zero
size GL surface initialization. Ozone-GBM wasn't previously working because of
that but now works like a charm ("[  PASSED  ] 94 tests").

This CL also fixes gpu_unittests under Ozone-GBM ("[  PASSED  ] 2544 tests")
and cleans a bit the message loop creation, bringing it to run earlier in the
RunTestSuite.

BUG=471261
TEST=gl_tests, gpu_unittests on both GBM and X11 (Linux)
NOTRY=true

Review URL: https://codereview.chromium.org/1025523005

Cr-Commit-Position: refs/heads/master@{#324925}

0 files changed, 0 insertions, 0 deletions