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

testing/buildbot/gn_isolate_map.pyl

 ## 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.
 
 # gn_isolate_map.pyl - A mapping of Ninja build target names to GN labels and
 # test type classifications for the tests that are run on the bots.
 #
 # This mapping is used by MB so that we can uniformly refer to test binaries
 # by their Ninja target names in the recipes and not need to worry about how
 # they are referred to in GN or GYP specifically (the GYP target name is pretty
@@ skipping 540 matching lines @@
     "type": "windowed_test_launcher",
   },
   "media_mojo_shell_unittests": {
     "label": "//media/mojo/services:media_mojo_shell_unittests",
     "type": "console_test_launcher",
   },
   "media_blink_unittests": {
     "label": "//media/blink:media_blink_unittests",
     "type": "windowed_test_launcher",
   },
+  "media_router_tests": {
+    "label": "//chrome/test/media_router:media_router_tests",
+    "type": "script",
+    "script": "//chrome/test/media_router/internal/media_router_tests.py",
+    "args": [
+      "--extension",
+      "mr_extension/",
+      "--test_binary",
+      "./browser_tests",
+    ],
+  },
   "midi_unittests": {
     "label": "//media/midi:midi_unittests",
     "type": "windowed_test_launcher",
   },
   "mini_installer": {
     "label": "//chrome/installer/mini_installer:mini_installer",
     "type": "additional_compile_target",
   },
   "mojo_common_unittests": {
     "label": "//mojo/common:mojo_common_unittests",
@@ skipping 370 matching lines @@
   },
   "wm_unittests": {
     "label": "//ui/wm:wm_unittests",
     "type": "windowed_test_launcher",
   },
   "wtf_unittests": {
     "label": "//third_party/WebKit/Source/wtf:wtf_unittests",
     "type": "console_test_launcher",
   },
 }