Ensure tests have an active task runner

chrome/browser/font_family_cache_unittest.cc

 // Copyright 2014 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/font_family_cache.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/test/base/testing_pref_service_syncable.h"
 #include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 class TestingFontFamilyCache : public FontFamilyCache {
  public:
   explicit TestingFontFamilyCache(Profile* profile)
       : FontFamilyCache(profile), fetch_font_count_(0) {}
   ~TestingFontFamilyCache() override {}
   base::string16 FetchFont(const char* script, const char* map_name) override {
     ++fetch_font_count_;
     return FontFamilyCache::FetchFont(script, map_name);
   }
 
   int fetch_font_count_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TestingFontFamilyCache);
 };
 
 }  // namespace
 
 // Tests that the cache is correctly set and cleared.
 TEST(FontFamilyCacheTest, Caching) {
+  content::TestBrowserThreadBundle thread_bundle_;
   TestingProfile profile;
   TestingFontFamilyCache cache(&profile);
   TestingPrefServiceSyncable* prefs = profile.GetTestingPrefService();
 
   std::string font1("font 1");
   std::string font2("font 2");
   std::string map_name("webkit.webprefs.fonts.pictograph");
   std::string script("Zzyxca");
   std::string pref_name(map_name + '.' + script);
   std::string pref_name2(map_name + '.' + "adsf");
@@ skipping 22 matching lines @@
   EXPECT_EQ(font1, result);
   EXPECT_EQ(1, cache.fetch_font_count_);
 
   // Changing the preferences invalidates the cache.
   prefs->SetString(pref_name.c_str(), font2.c_str());
   result = base::UTF16ToUTF8(
       cache.FetchAndCacheFont(script.c_str(), map_name.c_str()));
   EXPECT_EQ(font2, result);
   EXPECT_EQ(2, cache.fetch_font_count_);
 }