SimpleCache: read small files all at once.

net/disk_cache/simple/simple_experiment.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 "net/disk_cache/simple/simple_experiment.h"
 
 #include <map>
 #include <string>
 
 #include "base/metrics/field_trial.h"
 #include "base/metrics/field_trial_param_associator.h"
+#include "base/metrics/field_trial_params.h"
 #include "base/strings/string_number_conversions.h"
 
 namespace disk_cache {
 
 const base::Feature kSimpleSizeExperiment = {"SimpleSizeExperiment",
                                              base::FEATURE_DISABLED_BY_DEFAULT};
 const char kSizeMultiplierParam[] = "SizeMultiplier";
 
+const base::Feature kSimpleCachePrefetchExperiment = {
+    "GetSimpleCachePrefetchExperiment", base::FEATURE_DISABLED_BY_DEFAULT};
+const char kSimplePrefetchBytesParam[] = "Bytes";
+
 namespace {
 
 // Returns true if the experiment is found and properly defined.
 bool CheckForSimpleSizeExperiment(disk_cache::SimpleExperiment* experiment) {
   DCHECK_EQ(disk_cache::SimpleExperimentType::NONE, experiment->type);
   DCHECK_EQ(0u, experiment->param);
 
   if (!base::FeatureList::IsEnabled(kSimpleSizeExperiment))
     return false;
 
@@ skipping 24 matching lines @@
 SimpleExperiment GetSimpleExperiment(net::CacheType cache_type) {
   SimpleExperiment experiment;
 
   if (cache_type != net::DISK_CACHE)
     return experiment;
 
   CheckForSimpleSizeExperiment(&experiment);
   return experiment;
 }
 
+int GetSimpleCachePrefetchSize() {
+  return base::GetFieldTrialParamByFeatureAsInt(kSimpleCachePrefetchExperiment,

[pasko, 2017/07/18 14:02:57]

please also add a test that sets the experiment param differently and confirms
that things work on the SSEntry level.

[Maks Orlovich, 2017/07/25 16:06:29]

Done.

+                                                kSimplePrefetchBytesParam, 0);
+}
+
 }  // namespace disk_cache