Use allSinks to find a sink in kFindSinkScript.

chrome/test/media_router/media_router_integration_browsertest.cc

 // 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.
 
 #include "chrome/test/media_router/media_router_integration_browsertest.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
@@ skipping 65 matching lines @@
 const char kGetRouteIdScript[] =
     "var routes = window.document.getElementById('media-router-container')."
     "  routeList;"
     "for (var i=0; i<routes.length; i++) {"
     "  if (routes[i].sinkId == '%s') {"
     "    domAutomationController.send(routes[i].id);"
     "  }"
     "}"
     "domAutomationController.send('');";
 const char kFindSinkScript[] =
-    "var sinks = document.getElementById('media-router-container')."
-    "  shadowRoot.getElementById('sink-list').getElementsByTagName('span');"
-    "for (var i=0; i<sinks.length; i++) {"
-    "  if (sinks[i].textContent.trim() == '%s') {"
-    "    domAutomationController.send(true);"
-    "}}"
+    "var sinkList = document.getElementById('media-router-container')."
+    "  shadowRoot.getElementById('sink-list');"
+    "if (sinkList) {"
+    "  var sinks = sinkList.getElementsByTagName('span');"
+    "  for (var i=0; i<sinks.length; i++) {"
+    "    if (sinks[i].textContent.trim() == '%s') {"
+    "      domAutomationController.send(true);"
+    "}}}"
     "domAutomationController.send(false);";
 const char kCheckDialogLoadedScript[] =
     "var container = document.getElementById('media-router-container');"
     "/** Wait until media router container is not undefined and "
     "*   deviceMissingUrl is not undefined, "
     "*   once deviceMissingUrl is not undefined, which means "
     "*   the dialog is fully loaded."
     "*/"
     "if (container != undefined && container.deviceMissingUrl != undefined) {"
     "  domAutomationController.send(true);"
@@ skipping 527 matching lines @@
 
   MediaRouterDialogControllerImpl* controller =
       MediaRouterDialogControllerImpl::GetOrCreateForWebContents(web_contents);
   EXPECT_TRUE(controller->IsShowingMediaRouterDialog());
   WaitUntilSinkDiscoveredOnUI();
   controller->HideMediaRouterDialog();
   CheckStartFailed(web_contents, "NotFoundError", "No screens found.");
 }
 
 }  // namespace media_router