[Media Router] Do not issue a tab mirroring sinks query if tab is not valid.

chrome/browser/ui/webui/media_router/media_router_ui_unittest.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 "base/bind.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/media/router/media_route.h"
 #include "chrome/browser/media/router/mock_media_router.h"
 #include "chrome/browser/media/router/route_request_result.h"
 #include "chrome/browser/media/router/test_helper.h"
+#include "chrome/browser/sessions/session_tab_helper.h"
 #include "chrome/browser/ui/webui/media_router/media_router_ui.h"
 #include "chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h"
 #include "chrome/grit/generated_resources.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "content/public/test/test_web_ui.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/extension_builder.h"
 #include "extensions/common/test_util.h"
@@ skipping 21 matching lines @@
   ~MediaRouterUITest() override {
     EXPECT_CALL(mock_router_, UnregisterMediaSinksObserver(_))
         .Times(AnyNumber());
     EXPECT_CALL(mock_router_, UnregisterMediaRoutesObserver(_))
         .Times(AnyNumber());
   }
 
   void CreateMediaRouterUI(Profile* profile) {
     initiator_.reset(content::WebContents::Create(
         content::WebContents::CreateParams(profile)));
+    SessionTabHelper::CreateForWebContents(initiator_.get());
     web_contents_.reset(content::WebContents::Create(
         content::WebContents::CreateParams(profile)));
     web_ui_.set_web_contents(web_contents_.get());
     media_router_ui_.reset(new MediaRouterUI(&web_ui_));
     message_handler_.reset(
         new MediaRouterWebUIMessageHandler(media_router_ui_.get()));
     EXPECT_CALL(mock_router_, RegisterMediaSinksObserver(_))
         .WillRepeatedly(Return(true));
     EXPECT_CALL(mock_router_, RegisterMediaRoutesObserver(_))
         .Times(AnyNumber());
@@ skipping 221 matching lines @@
 }
 
 TEST_F(MediaRouterUITest, GetExtensionNameEmptyWhenNotExtensionURL) {
   GURL url = GURL("https://www.google.com");
   scoped_ptr<extensions::ExtensionRegistry> registry =
       make_scoped_ptr(new extensions::ExtensionRegistry(nullptr));
 
   EXPECT_EQ("", MediaRouterUI::GetExtensionName(url, registry.get()));
 }
 }  // namespace media_router