Add media router common classes and unittests.

BUILD.gn

 # Copyright (c) 2013 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 104 matching lines @@
     deps += [ "//ui/wm:wm_unittests" ]
   }
 
   if (use_ozone) {
     deps += [
       "//ui/ozone",
       "//ui/ozone/demo",  # GN only
     ]
   }
 
+  if (enable_media_router) {
+    deps += [
+      "//chrome/browser/media/router/",
+      "//chrome/browser/media/router:unit_tests",
+    ]
+  }
+
   if (is_win || is_mac || is_chromeos) {
     # RLZ works on these platforms.
     # TODO(GYP): Is this target needed, or pulled in automatically?
     deps += [ "//rlz:rlz_lib" ]
   }
 
   if (is_android) {
     deps += [
       "//base/android/linker:chromium_android_linker",
       "//build/android/gyp/test:hello_world",
@@ skipping 190 matching lines @@
       "//ui/touch_selection:ui_touch_selection_unittests",  # PASSES 2/25/2015
       "//ui/views:views_unittests",  # PASSES (*) 2/25/2015
       "//ui/wm:wm_unittests",  # PASSES 2/25/2015
       "//url:url_unittests",  # PASSES 2/25/2015
 
       # Note:
       # (*) Fails but failures match GYP build at time of testing.
     ]
   }
 }