Unit test FindInPageMediator.

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

 # Copyright 2017 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("find_in_page") {
   sources = [
     "find_in_page_coordinator.h",
     "find_in_page_coordinator.mm",
     "find_in_page_mediator.h",
     "find_in_page_mediator.mm",
@@ skipping 30 matching lines @@
     "//ios/clean/chrome/browser/ui",
     "//ios/clean/chrome/browser/ui/actions",
     "//ios/clean/chrome/browser/ui/animators",
     "//ios/clean/chrome/browser/ui/commands",
     "//ios/clean/chrome/browser/ui/presenters",
     "//ui/base",
   ]
   libs = [ "UIKit.framework" ]
   configs += [ "//build/config/compiler:enable_arc" ]
 }
+
+source_set("unit_tests") {
+  sources = [
+    "find_in_page_mediator_unittest.mm",
+  ]
+  deps = [
+    ":find_in_page",
+    ":find_in_page_ui",
+    "//base",
+    "//ios/chrome/browser/web_state_list",
+    "//ios/chrome/browser/web_state_list:test_support",
+    "//testing/gtest",
+    "//third_party/ocmock",
+  ]
+  configs += [ "//build/config/compiler:enable_arc" ]
+  testonly = true
+}