Add unittest to test CWVWebView.

ios/web_view/test/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.
+
+import("//ios/build/config.gni")
+import("//build/config/ios/rules.gni")
+import("//testing/test.gni")
+
+group("all_tests") {
+  testonly = true
+  deps = [
+    ":ios_web_view_unitttests",
+  ]
+}
+
+test("ios_web_view_unitttests") {
+  testonly = true
+  sources = [
+    "boolean_observer.h",
+    "boolean_observer.mm",
+    "chrome_web_view_kvo_unittest.mm",
+    "chrome_web_view_test.h",
+    "chrome_web_view_test.mm",
+    "test_server.cc",
+    "test_server.h",
+    "web_view_interaction_test_util.h",
+    "web_view_interaction_test_util.mm",
+  ]
+
+  deps = [
+    "//base",
+    "//base/test:run_all_unittests",
+    "//ios/testing:ios_test_support",
+    "//ios/web_view:web_view+link",
+    "//net",
+    "//net:test_support",
+    "//testing/gtest",
+  ]
+
+  bundle_deps = [ "//ios/web_view:web_view+bundle" ]
+
+  configs += [ "//build/config/compiler:enable_arc" ]
+
+  assert_no_deps = ios_assert_no_deps
+}