Use ScopedTaskEnvironment instead of MessageLoop in components unit tests.

components/omnibox/browser/history_quick_provider_performance_unittest.cc

 // Copyright 2016 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 "components/omnibox/browser/history_quick_provider.h"
 
 #include <memory>
 #include <random>
 #include <string>
 
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_task_environment.h"
 #include "components/history/core/browser/history_backend.h"
 #include "components/history/core/browser/history_database.h"
 #include "components/history/core/browser/history_service.h"
 #include "components/history/core/test/history_service_test_util.h"
 #include "components/omnibox/browser/fake_autocomplete_provider_client.h"
 #include "components/omnibox/browser/history_test_util.h"
 #include "components/omnibox/browser/in_memory_url_index_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/perf/perf_test.h"
 
@@ skipping 66 matching lines @@
   void PrintMeasurements(const std::string& trace_name,
                          const std::vector<base::TimeDelta>& measurements);
 
   history::HistoryBackend* history_backend() {
     return client_->GetHistoryService()->history_backend_.get();
   }
 
  private:
   base::TimeDelta RunTest(const base::string16& text);
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<FakeAutocompleteProviderClient> client_;
 
   scoped_refptr<HistoryQuickProvider> provider_;
 
   DISALLOW_COPY_AND_ASSIGN(HQPPerfTestOnePopularURL);
 };
 
 void HQPPerfTestOnePopularURL::SetUp() {
   if (base::ThreadTicks::IsSupported())
     base::ThreadTicks::WaitUntilInitialized();
@@ skipping 93 matching lines @@
   RunAllTests(prefixes.begin(), prefixes.end());
 }
 
 TEST_F(HQPPerfTestOnePopularURL, Backspacing) {
   std::string test_url = GeneratePopularURLRow().url().spec();
   StringPieces prefixes = AllPrefixes(test_url);
   RunAllTests(prefixes.rbegin(), prefixes.rend());
 }
 
 }  // namespace history