Enable Ozone software implementation in GYP

ui/gfx/gfx.gyp

Index: ui/gfx/gfx.gyp
diff --git a/ui/gfx/gfx.gyp b/ui/gfx/gfx.gyp
index 48f0b2f98811f9864eb45beb51d30458ad5ae598..6b6f2f297a8b4d8764109c870e193256c486cf1a 100644
--- a/ui/gfx/gfx.gyp
+++ b/ui/gfx/gfx.gyp
@@ -135,6 +135,16 @@
         'matrix3_f.cc',
         'matrix3_f.h',
         'native_widget_types.h',
+        'ozone/impl/drm_skbitmap_ozone.cc',
+        'ozone/impl/drm_skbitmap_ozone.h',
+        'ozone/impl/drm_wrapper_ozone.cc',
+        'ozone/impl/drm_wrapper_ozone.h',
+        'ozone/impl/hardware_display_controller_ozone.cc',
+        'ozone/impl/hardware_display_controller_ozone.h',
+        'ozone/impl/software_surface_factory_ozone.cc',
+        'ozone/impl/software_surface_factory_ozone.h',
+        'ozone/impl/software_surface_ozone.cc',
+        'ozone/impl/software_surface_ozone.h',
         'ozone/surface_factory_ozone.cc',
         'ozone/surface_factory_ozone.h',
         'pango_util.cc',
@@ -357,6 +367,11 @@
             '<(DEPTH)/build/linux/system.gyp:pangocairo',
           ],
         }],
+        ['use_ozone==1', {
+          'dependencies': [
+          '<(DEPTH)/build/linux/system.gyp:dridrm',
+          ],
+        }],
       ],
       'target_conditions': [
         # Need 'target_conditions' to override default filename_rules to include