Add a data_dep for osmesa to //ui/gl and run ui_unittests.

mojo/tools/data/apptests

 # This file contains a list of Mojo apptests. For description of the file
 # format, see `mojo_test` in devtools.
 
 tests = [
   {
     "test": "mojo:asset_bundle_apptests",
   },
   {
     "test": "mojo:authenticating_url_loader_interceptor_apptests",
   },
@@ skipping 34 matching lines @@
     "test": "mojo:log_impl_apptests"
   },
   {
     "test": "mojo:mojio_apptests",
   },
   {
     "test": "mojo:moterm_apptests",
     "shell-args": ["--args-for=mojo:native_viewport_service --use-headless-config --use-osmesa"],
   },
   {
+    "test": "mojo:network_service_apptests",
+  },
+  {
     "test": "mojo:prediction_apptests",
   },
   {
-    "test": "mojo:network_service_apptests",
+    "test": "mojo:ui_unittests",
+    "shell-args": ["--args-for=mojo:native_viewport_service --use-headless-config --use-osmesa"],
+  },
+  {
+    "test": "mojo:url_response_disk_cache_apptests",
   },
   {
     "test": "mojo:versioning_apptests",
   },
-  {
-    "test": "mojo:url_response_disk_cache_apptests",
-  },
 ]
 
 if target_os == 'linux':
   tests += [
     {
       "test": "mojo:example_apptests",
       "name": "mojo:example_apptests (python_example_service)",
       # ExampleApplicationTest.CheckCommandLineArg checks --example_apptest_arg.
       "test-args": ["--example_apptest_arg"],
       "shell-args": [
@@ skipping 44 matching lines @@
       # These tests rely on various things in /bin.
       "test": "mojo:native_support_apptests",
     },
     {
       # https://github.com/domokit/mojo/issues/61
       # Sometime the shell get a trucated application when exposed through the
       # http server.
       "test": "mojo:shell_apptests",
     },
   ]