**STILLBAKING** Fix SimpleCache eviction performance.

net/disk_cache/backend_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 <stdint.h>
 
 #include "base/files/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 2926 matching lines @@
 
 TEST_F(DiskCacheBackendTest, BackendEviction) {
   BackendEviction();
 }
 
 TEST_F(DiskCacheBackendTest, MemoryOnlyBackendEviction) {
   SetMemoryOnlyMode();
   BackendEviction();
 }
 
-// TODO(gavinp): Enable BackendEviction test for simple cache after performance
-// problems are addressed. See crbug.com/588184 for more information.
+TEST_F(DiskCacheBackendTest, SimpleCacheBackendEviction) {
+  SetSimpleCacheMode();
+  BackendEviction();
+}
 
 TEST_F(DiskCacheTest, Backend_UsageStatsTimer) {
   MessageLoopHelper helper;
 
   ASSERT_TRUE(CleanupCacheDir());
   scoped_ptr<disk_cache::BackendImpl> cache;
   cache.reset(new disk_cache::BackendImpl(
       cache_path_, base::ThreadTaskRunnerHandle::Get(), NULL));
   ASSERT_TRUE(NULL != cache.get());
   cache->SetUnitTestMode();
@@ skipping 744 matching lines @@
 // after closing.
 // NOTE: IF THIS TEST IS FLAKY THEN IT IS FAILING. See https://crbug.com/416940
 TEST_F(DiskCacheBackendTest, SimpleCacheDeleteQuickly) {
   SetSimpleCacheMode();
   for (int i = 0; i < 100; ++i) {
     InitCache();
     cache_.reset();
     EXPECT_TRUE(CleanupCacheDir());
   }
 }