Added unittest for ui/gl.

ui/gl/BUILD.gn

Index: ui/gl/BUILD.gn
diff --git a/ui/gl/BUILD.gn b/ui/gl/BUILD.gn
index efee0ee1c3135b13ae3d4c565a63126c54ba620b..76ed117d9024b26a1a51ffb2b98ce4745bb97f45 100644
--- a/ui/gl/BUILD.gn
+++ b/ui/gl/BUILD.gn
@@ -3,6 +3,8 @@
 # found in the LICENSE file.
 
 import("//build/config/ui.gni")
+import("//testing/test.gni")
+
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
@@ -276,6 +278,19 @@ source_set("gl_unittest_utils") {
   ]
 }
 
+test("gl_unittests") {
+  sources = [
+    "test/run_all_unittests.cc",
+  ]
+
+  deps = [
+    ":gl",
+    "//base",
+    "//base/test:test_support",
+    "//testing/gtest",
+  ]
+}
+
 if (is_android) {
   generate_jar_jni("surface_jni_headers") {
     jni_package = "ui/gl"