Implement DRM Native Pixmap using prime buffer

ui/ozone/platform/drm/ozone_platform_gbm.cc

Index: ui/ozone/platform/drm/ozone_platform_gbm.cc
diff --git a/ui/ozone/platform/drm/ozone_platform_gbm.cc b/ui/ozone/platform/drm/ozone_platform_gbm.cc
index 6ff216a75fe8660a47fd6f2e15b25c28b49952f5..fddd99178f0bcc465cf77f48eb150b3a97cc74c2 100644
--- a/ui/ozone/platform/drm/ozone_platform_gbm.cc
+++ b/ui/ozone/platform/drm/ozone_platform_gbm.cc
@@ -121,17 +121,6 @@ class OzonePlatformGbm : public OzonePlatform {
     return make_scoped_ptr(
         new DrmNativeDisplayDelegate(display_manager_.get()));
   }
-  base::ScopedFD OpenClientNativePixmapDevice() const override {
-#if defined(USE_VGEM_MAP)
-    int vgem_fd = drmOpenWithType("vgem", nullptr, DRM_NODE_RENDER);
-    if (vgem_fd < 0) {
-      PLOG(ERROR) << "Failed to find vgem device";
-      vgem_fd = -1;
-    }
-    return base::ScopedFD(vgem_fd);
-#endif
-    return base::ScopedFD();
-  }
   void InitializeUI() override {
     device_manager_ = CreateDeviceManager();
     window_manager_.reset(new DrmWindowHostManager());