Restore disk_cache perf tests runnability.

net/disk_cache/disk_cache_perftest.cc

 // Copyright (c) 2011 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 <limits>
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/hash.h"
 #include "base/process/process_metrics.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/strings/string_util.h"
 #include "base/test/perf_time_logger.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/test/test_file_util.h"
 #include "base/threading/thread.h"
 #include "net/base/cache_type.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/base/test_completion_callback.h"
 #include "net/disk_cache/blockfile/backend_impl.h"
 #include "net/disk_cache/blockfile/block_files.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/disk_cache_test_base.h"
@@ skipping 56 matching lines @@
   const size_t kFdLimitForCacheTests = 8192;
 
   const int kNumEntries = 1000;
   const int kHeadersSize = 800;
   const int kBodySize = 256 * 1024 - 1;
 
   std::vector<TestEntry> entries_;
 
  private:
   const size_t saved_fd_limit_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 };
 
 // Creates num_entries on the cache, and writes kHeaderSize bytes of metadata
 // and up to kBodySize of data to each entry.
 bool DiskCachePerfTest::TimeWrite() {
   // TODO(gavinp): This test would be significantly more realistic if it didn't
   // do single reads and writes. Perhaps entries should be written 64kb at a
   // time. As well, not all entries should be created and written essentially
   // simultaneously; some number of entries in flight at a time would be a
   // likely better testing load.
@@ skipping 235 matching lines @@
     index.SetMaxSize(kEntries);
     index.UpdateEntrySize(0, 1u);
     evict_elapsed_ms += timer.Elapsed().InMillisecondsF();
   }
 
   LOG(ERROR) << "Average time to evict:" << (evict_elapsed_ms / iterations)
              << "ms";
 }
 
 }  // namespace