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

mojo/tools/data/apptests

Index: mojo/tools/data/apptests
diff --git a/mojo/tools/data/apptests b/mojo/tools/data/apptests
index 3456c2c8fd082b94a61b525a8af454830b6a0c43..7c89653666a51dc71568b8a112b5ebeb8deb9208 100644
--- a/mojo/tools/data/apptests
+++ b/mojo/tools/data/apptests
@@ -52,17 +52,21 @@ tests = [
     "shell-args": ["--args-for=mojo:native_viewport_service --use-headless-config --use-osmesa"],
   },
   {
-    "test": "mojo:prediction_apptests",
+    "test": "mojo:network_service_apptests",
   },
   {
-    "test": "mojo:network_service_apptests",
+    "test": "mojo:prediction_apptests",
   },
   {
-    "test": "mojo:versioning_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",
+  },
 ]
 
 if target_os == 'linux':