Update the build rule for media router tests (e2e) and the mapping.

chrome/test/media_router/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.
 
+group("media_router_tests") {
+  testonly = true
+  data_deps = [
+    "//chrome/test:browser_tests",
+  ]
+  data = [
+    "$root_out_dir/mr_extension/",
+    "internal/",
+    "../../../media/test/data/player.html",
+    "../../../media/test/data/bear-vp9-opus.webm",
+  ]
+}
+
 # Browser test resource files.
 media_router_integration_test_resources = [
   "resources/basic_test.html",
   "resources/close_route_with_error_on_send.json",
   "resources/common.js",
   "resources/fail_create_route.json",
   "resources/fail_reconnect_session.html",
   "resources/fail_reconnect_session.json",
   "resources/no_provider.json",
   "resources/no_sinks.json",
@@ skipping 37 matching lines @@
   ]
   deps = [
     ":browser_tests_resource_files",
     "//chrome/browser/media/router:test_support",
     "//chrome/test:test_support",
     "//chrome/test:test_support_ui",
     "//skia",
     "//testing/gtest",
   ]
 }