predictors: Add an about:flags flag for speculative prefetch.

chrome/browser/about_flags.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 "chrome/browser/about_flags.h"
 
 #include <iterator>
 #include <map>
 #include <set>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/feature_list.h"
 #include "base/i18n/base_i18n_switches.h"
 #include "base/macros.h"
 #include "base/memory/singleton.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/metrics_hashes.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task_scheduler/switches.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
 #include "chrome/browser/ntp_snippets/ntp_snippets_features.h"
+#include "chrome/browser/predictors/resource_prefetch_common.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_content_client.h"
 #include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/features.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/autofill/core/browser/autofill_experiments.h"
 #include "components/autofill/core/common/autofill_switches.h"
@@ skipping 630 matching lines @@
      prerender::kNoStatePrefetchFeatureModeParameterSimpleLoad}};
 
 const FeatureEntry::FeatureVariation kNoStatePrefetchFeatureVariations[] = {
     {"No-state prefetch", kNoStatePrefetchEnabled,
      arraysize(kNoStatePrefetchEnabled), nullptr},
     {"Prerender", kNoStatePrefetchPrerender,
      arraysize(kNoStatePrefetchPrerender), nullptr},
     {"Simple load", kNoStatePrefetchSimpleLoad,
      arraysize(kNoStatePrefetchSimpleLoad), nullptr}};
 
+const FeatureEntry::FeatureParam kSpeculativeResourcePrefetchingPrefetching[] =
+    {{predictors::kModeParamName, predictors::kPrefetchingMode}};
+
+const FeatureEntry::FeatureParam kSpeculativeResourcePrefetchingLearning[] = {
+    {predictors::kModeParamName, predictors::kLearningMode}};
+
+const FeatureEntry::FeatureVariation
+    kSpeculativeResourcePrefetchingFeatureVariations[] = {
+        {"Prefetching", kSpeculativeResourcePrefetchingPrefetching,
+         arraysize(kSpeculativeResourcePrefetchingPrefetching), nullptr},
+        {"Learning", kSpeculativeResourcePrefetchingLearning,
+         arraysize(kSpeculativeResourcePrefetchingLearning), nullptr}};
+
 #if defined(OS_ANDROID)
 const FeatureEntry::FeatureParam
 kAutofillCreditCardPopupLayoutFeatureVariationIconAtStart[] = {
   {"is_credit_card_icon_at_start", "true"}};
 
 const FeatureEntry::FeatureParam
 kAutofillCreditCardPopupLayoutFeatureVariationDropdownItemHeight[] = {
   {"dropdown_item_height", "56"}};
 
 const FeatureEntry::FeatureParam
@@ skipping 1631 matching lines @@
      FEATURE_VALUE_TYPE(omnibox::kOmniboxEntitySuggestions)},
 #endif  // defined(OS_CHROMEOS) || defined(OS_LINUX) || defined(OS_MACOSX) ||
         // defined(OS_WIN)
 
 #if defined(OS_ANDROID)
     {"enable-custom-feedback-ui", IDS_FLAGS_ENABLE_CUSTOM_FEEDBACK_UI_NAME,
      IDS_FLAGS_ENABLE_CUSTOM_FEEDBACK_UI_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(chrome::android::kCustomFeedbackUi)},
 #endif  // OS_ANDROID
 
+    {"enable-resource-prefetch", IDS_FLAGS_SPECULATIVE_PREFETCH_NAME,
+     IDS_FLAGS_SPECULATIVE_PREFETCH_DESCRIPTION, kOsAll,
+     FEATURE_WITH_VARIATIONS_VALUE_TYPE(
+         predictors::kSpeculativeResourcePrefetchingFeature,
+         kSpeculativeResourcePrefetchingFeatureVariations,
+         "SpeculativeResourcePrefetchingValidation")},
+
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in
     // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.
 };
 
 class FlagsStateSingleton {
  public:
   FlagsStateSingleton()
       : flags_state_(kFeatureEntries, arraysize(kFeatureEntries)) {}
   ~FlagsStateSingleton() {}
@@ skipping 188 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags