[Presentation API] Add browser tests for 1-UA mode

chrome/test/media_router/BUILD.gn

Index: chrome/test/media_router/BUILD.gn
diff --git a/chrome/test/media_router/BUILD.gn b/chrome/test/media_router/BUILD.gn
index 73d4675eb8f9a9f4f1618fa1a7a353931b931b61..7022a158f018bc1b174b85f4d50f21a8500e72b1 100644
--- a/chrome/test/media_router/BUILD.gn
+++ b/chrome/test/media_router/BUILD.gn
@@ -40,6 +40,7 @@ media_router_integration_test_resources = [
   "resources/no_provider.json",
   "resources/no_sinks.json",
   "resources/no_supported_sinks.json",
+  "resources/presentation_receiver.html",
   "resources/route_creation_timed_out.json",
 ]
 
@@ -74,6 +75,7 @@ source_set("media_router_browsertests") {
     "media_router_integration_browsertest.cc",
     "media_router_integration_browsertest.h",
     "media_router_integration_ui_browsertest.cc",
+    "media_router_one_ua_integration_browsertest.cc",
     "test_media_sinks_observer.cc",
     "test_media_sinks_observer.h",
   ]