**NOTFORLANDING** Example slowdown for disk cache stress test

net/disk_cache/simple/simple_synchronous_entry.cc

 // Copyright (c) 2013 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 "net/disk_cache/simple/simple_synchronous_entry.h"
 
 #include <algorithm>
 #include <cstring>
 #include <functional>
 #include <limits>
 
+#include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_util.h"
 #include "base/hash.h"
 #include "base/location.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/sha1.h"
 #include "base/strings/stringprintf.h"
 #include "base/timer/elapsed_timer.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/simple/simple_backend_version.h"
 #include "net/disk_cache/simple/simple_histogram_macros.h"
 #include "net/disk_cache/simple/simple_util.h"
 #include "third_party/zlib/zlib.h"
 
+#include <unistd.h>
+
 using base::File;
 using base::FilePath;
 using base::Time;
 
 namespace {
 
 // Used in histograms, please only add entries at the end.
 enum OpenEntryResult {
   OPEN_ENTRY_SUCCESS = 0,
   OPEN_ENTRY_PLATFORM_FILE_ERROR = 1,
@@ skipping 221 matching lines @@
   out_results->result = sync_entry->InitializeForCreate(
       had_index, &out_results->entry_stat);
   if (out_results->result != net::OK) {
     if (out_results->result != net::ERR_FILE_EXISTS)
       sync_entry->Doom();
     delete sync_entry;
     out_results->sync_entry = NULL;
     return;
   }
   out_results->sync_entry = sync_entry;
+  if (base::CommandLine::ForCurrentProcess()-> HasSwitch(
+          "simple-cache-slower-creates")) {
+    usleep(20 * 1000);
+  }
 }
 
 // static
 int SimpleSynchronousEntry::DoomEntry(const FilePath& path,
                                       uint64_t entry_hash) {
   const bool deleted_well = DeleteFilesForEntryHash(path, entry_hash);
   return deleted_well ? net::OK : net::ERR_FAILED;
 }
 
 // static
@@ skipping 1188 matching lines @@
   range.offset = offset;
   range.length = len;
   range.data_crc32 = data_crc32;
   range.file_offset = data_file_offset;
   sparse_ranges_.insert(std::make_pair(offset, range));
 
   return true;
 }
 
 }  // namespace disk_cache