Ensure tests have an active task runner

chrome/browser/thumbnails/thumbnail_service_unittest.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 "chrome/browser/thumbnails/thumbnail_service_impl.h"
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/history/top_sites_factory.h"
 #include "chrome/browser/history/top_sites_impl.h"
 #include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-typedef testing::Test ThumbnailServiceTest;
+class ThumbnailServiceTest : public testing::Test {
+  content::TestBrowserThreadBundle thread_bundle_;
+};
 
 namespace {
 
 // A mock version of TopSitesImpl, used for testing
 // ShouldAcquirePageThumbnail().
 class MockTopSites : public history::TopSitesImpl {
  public:
   explicit MockTopSites(Profile* profile)
       : history::TopSitesImpl(profile, history::PrepopulatedPageList()),
         capacity_(1) {}
@@ skipping 99 matching lines @@
   good_score.at_top = true;
   good_score.good_clipping = true;
   good_score.boring_score = 0.0;
   good_score.load_completed = true;
   profile.AddKnownURL(kGoodURL, good_score);
 
   // Should be false, as the existing thumbnail is good enough (i.e. don't
   // need to replace the existing thumbnail which is new and good).
   EXPECT_FALSE(thumbnail_service->ShouldAcquirePageThumbnail(kGoodURL));
 }