Make The task manager browser tests for the print preview work under --site-per-process

chrome/browser/printing/print_preview_dialog_controller_browsertest.cc

 // Copyright (c) 2012 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_helpers.h"
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 355 matching lines @@
   EXPECT_EQ(task_management::Task::RENDERER, pre_existing_task->GetType());
   const base::string16 pre_existing_title = pre_existing_task->title();
   const base::string16 expected_prefix = GetExpectedPrefix();
   EXPECT_TRUE(base::StartsWith(pre_existing_title,
                                expected_prefix,
                                base::CompareCase::INSENSITIVE_ASCII));
 
   // Navigating away from the current page in the current tab for which a print
   // preview is displayed will cancel the print preview and hence the task
   // manger shouldn't show a printing task.
-  ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUINewTabURL));
+  ui_test_utils::NavigateToURL(browser(), GURL("about:blank"));
   EXPECT_EQ(2U, GetTrackedTags().size());
   EXPECT_EQ(2U, task_manager.tasks().size());
 
   // Now start another print preview after the had already been created and
   // validated that a corresponding task is reported.
   PrintPreview();
   EXPECT_EQ(3U, GetTrackedTags().size());
   EXPECT_EQ(3U, task_manager.tasks().size());
   const task_management::Task* task = task_manager.tasks().back();
   EXPECT_EQ(task_management::Task::RENDERER, task->GetType());
   const base::string16 title = task->title();
   EXPECT_TRUE(base::StartsWith(title,
                                expected_prefix,
                                base::CompareCase::INSENSITIVE_ASCII));
 }
 
 }  // namespace
 
 #endif  // defined(ENABLE_TASK_MANAGER)