Allow to run ozone_demo on a Linux/Intel desktop

First, we need to enable Intel driver by building
Mesa 17.0.2 with --with-egl-platform=surfaceless
--with-dri-drivers=i965

BUG=733450
TEST=ozone_demo

$ cd ~/git/chromium/src
$ gn gen out/Release "--args=use_ozone=true ozone_platform_gbm=true
use_intel_minigbm=true"
$ ninja -C out/Release ozone_demo
$ export EGL_PLATFORM=surfaceless
$ out/Release/ozone_demo

Change-Id: Ic560b2b4f36701f3c159fd35e771d04c2e1ec97e
Reviewed-on: https://chromium-review.googlesource.com/886836Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Joone Hur <joone.hur@intel.com>
Cr-Commit-Position: refs/heads/master@{#534168}

third_party/minigbm/BUILD.gn

@@ -12,11 +12,15 @@ declare_args() {
   # system version, but when building on dev workstations or the Chrome
   # waterfall we bundle it because Ubuntu doesn't ship a usable version.
   use_system_minigbm = false
+  use_intel_minigbm = false
 }
 
 if (!use_system_minigbm) {
   config("minigbm_config") {
     include_dirs = [ "src" ]
+    if (use_intel_minigbm) {
+      defines = [ "DRV_I915" ]
+    }
   }
 
   shared_library("minigbm") {