Add more components_unittests to GN build

components/guest_view/browser/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 source_set("browser") {
   output_name = "guest_view_browser"
   sources = [
     "//components/guest_view/browser/guest_view.h",
     "//components/guest_view/browser/guest_view_base.cc",
     "//components/guest_view/browser/guest_view_base.h",
@@ skipping 18 matching lines @@
   ]
 }
 
 source_set("test_support") {
   testonly = true
   sources = [
     "//components/guest_view/browser/test_guest_view_manager.cc",
     "//components/guest_view/browser/test_guest_view_manager.h",
   ]
 
-  deps = [
+  public_deps = [
     ":browser",
     "//content/test:test_support",
   ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "guest_view_manager_unittest.cc",
+  ]
+  deps = [
+    ":test_support",
+    "//testing/gtest",
+  ]
+}