[ios] Unittest for TabGridMediator.

ios/clean/chrome/browser/ui/tab_grid/BUILD.gn

 # Copyright 2016 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("tab_grid") {
   sources = [
     "tab_grid_coordinator.h",
     "tab_grid_coordinator.mm",
     "tab_grid_mediator.h",
     "tab_grid_mediator.mm",
@@ skipping 47 matching lines @@
     "//ios/chrome/browser/ui/colors",
     "//ios/chrome/browser/ui/tab_switcher",
     "//ios/clean/chrome/browser/ui/actions",
     "//ios/clean/chrome/browser/ui/animators",
     "//ios/clean/chrome/browser/ui/commands",
     "//ios/clean/chrome/browser/ui/tab_collection:tab_collection_ui",
     "//ios/third_party/material_components_ios:material_components_ios",
     "//ui/base",
   ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+
+  sources = [
+    "tab_grid_mediator_unittest.mm",
+  ]
+
+  configs += [ "//build/config/compiler:enable_arc" ]
+
+  deps = [
+    ":tab_grid",
+    ":tab_grid_ui",
+    "//base",
+    "//base/test:test_support",
+    "//ios/chrome/test/base",
+    "//ios/shared/chrome/browser/tabs",
+    "//ios/shared/chrome/browser/tabs:test_support",
+    "//ios/web:test_support",
+    "//testing/gtest",
+    "//third_party/ocmock",
+  ]
+}