Remove the speculative resource prefetching code. This was experimental code added 1.5 years ago an…

chrome/browser/predictors/resource_prefetch_common.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/predictors/resource_prefetch_common.h"
-
-#include "base/command_line.h"
-#include "base/metrics/field_trial.h"
-#include "base/prefs/pref_service.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/common/chrome_switches.h"
-#include "chrome/common/pref_names.h"
-#include "content/public/browser/render_process_host.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/web_contents.h"
-
-namespace predictors {
-
-const char kSpeculativePrefetchingTrialName[] =
-    "SpeculativeResourcePrefetching";
-
-bool IsSpeculativeResourcePrefetchingEnabled(
-    Profile* profile,
-    ResourcePrefetchPredictorConfig* config) {
-  DCHECK(config);
-
-  // Off the record - disabled.
-  if (!profile || profile->IsOffTheRecord())
-    return false;
-
-  // If the user has explicitly disabled "predictive actions" - disabled.
-  if (!profile->GetPrefs() ||
-      !profile->GetPrefs()->GetBoolean(prefs::kNetworkPredictionEnabled)) {
-    return false;
-  }
-
-  // The config has the default params already set. The command line with just
-  // enable them with the default params.
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSpeculativeResourcePrefetching)) {
-    const std::string value =
-        CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-            switches::kSpeculativeResourcePrefetching);
-
-    if (value == switches::kSpeculativeResourcePrefetchingDisabled) {
-      return false;
-    } else if (value == switches::kSpeculativeResourcePrefetchingLearning) {
-      config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-      config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-      return true;
-    } else if (value == switches::kSpeculativeResourcePrefetchingEnabled) {
-      config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-      config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-      config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-      config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-      return true;
-    }
-  }
-
-  std::string trial = base::FieldTrialList::FindFullName(
-      kSpeculativePrefetchingTrialName);
-
-  if (trial == "LearningHost") {
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    return true;
-  } else if (trial == "LearningURL") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    return true;
-  } else if (trial == "Learning") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    return true;
-  } else if (trial == "PrefetchingHost") {
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-    return true;
-  } else if (trial == "PrefetchingURL") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    return true;
-  } else if (trial == "Prefetching") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-    return true;
-  } else if (trial == "PrefetchingLowConfidence") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-
-    config->min_url_visit_count = 1;
-    config->min_resource_confidence_to_trigger_prefetch = 0.5f;
-    config->min_resource_hits_to_trigger_prefetch = 1;
-    return true;
-  } else if (trial == "PrefetchingHighConfidence") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-
-    config->min_url_visit_count = 3;
-    config->min_resource_confidence_to_trigger_prefetch = 0.9f;
-    config->min_resource_hits_to_trigger_prefetch = 3;
-    return true;
-  } else if (trial == "PrefetchingMoreResources") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-
-    config->max_resources_per_entry = 100;
-    return true;
-  } else if (trial == "LearningSmallDB") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-
-    config->max_urls_to_track = 200;
-    config->max_hosts_to_track = 100;
-    return true;
-  } else if (trial == "PrefetchingSmallDB") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-
-    config->max_urls_to_track = 200;
-    config->max_hosts_to_track = 100;
-    return true;
-  } else if (trial == "PrefetchingSmallDBLowConfidence") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-
-    config->max_urls_to_track = 200;
-    config->max_hosts_to_track = 100;
-    config->min_url_visit_count = 1;
-    config->min_resource_confidence_to_trigger_prefetch = 0.5f;
-    config->min_resource_hits_to_trigger_prefetch = 1;
-    return true;
-  } else if (trial == "PrefetchingSmallDBHighConfidence") {
-    config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
-    config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
-    config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
-
-    config->max_urls_to_track = 200;
-    config->max_hosts_to_track = 100;
-    config->min_url_visit_count = 3;
-    config->min_resource_confidence_to_trigger_prefetch = 0.9f;
-    config->min_resource_hits_to_trigger_prefetch = 3;
-    return true;
-  }
-
-  return false;
-}
-
-NavigationID::NavigationID() : render_process_id(-1), render_view_id(-1) {
-}
-
-NavigationID::NavigationID(const NavigationID& other)
-    : render_process_id(other.render_process_id),
-      render_view_id(other.render_view_id),
-      main_frame_url(other.main_frame_url),
-      creation_time(other.creation_time) {
-}
-
-NavigationID::NavigationID(content::WebContents* web_contents)
-    : render_process_id(web_contents->GetRenderProcessHost()->GetID()),
-      render_view_id(web_contents->GetRenderViewHost()->GetRoutingID()),
-      main_frame_url(web_contents->GetURL()) {
-}
-
-bool NavigationID::is_valid() const {
-  return render_process_id != -1 && render_view_id != -1 &&
-      !main_frame_url.is_empty();
-}
-
-bool NavigationID::operator<(const NavigationID& rhs) const {
-  DCHECK(is_valid() && rhs.is_valid());
-  if (render_process_id != rhs.render_process_id)
-    return render_process_id < rhs.render_process_id;
-  else if (render_view_id != rhs.render_view_id)
-    return render_view_id < rhs.render_view_id;
-  else
-    return main_frame_url < rhs.main_frame_url;
-}
-
-bool NavigationID::operator==(const NavigationID& rhs) const {
-  DCHECK(is_valid() && rhs.is_valid());
-  return IsSameRenderer(rhs) && main_frame_url == rhs.main_frame_url;
-}
-
-bool NavigationID::IsSameRenderer(const NavigationID& other) const {
-  DCHECK(is_valid() && other.is_valid());
-  return render_process_id == other.render_process_id &&
-      render_view_id == other.render_view_id;
-}
-
-ResourcePrefetchPredictorConfig::ResourcePrefetchPredictorConfig()
-    : mode(0),
-      max_navigation_lifetime_seconds(60),
-      max_urls_to_track(500),
-      max_hosts_to_track(200),
-      min_url_visit_count(2),
-      max_resources_per_entry(50),
-      max_consecutive_misses(3),
-      min_resource_confidence_to_trigger_prefetch(0.8f),
-      min_resource_hits_to_trigger_prefetch(3),
-      max_prefetches_inflight_per_navigation(24),
-      max_prefetches_inflight_per_host_per_navigation(3) {
-}
-
-ResourcePrefetchPredictorConfig::~ResourcePrefetchPredictorConfig() {
-}
-
-bool ResourcePrefetchPredictorConfig::IsLearningEnabled() const {
-  return IsURLLearningEnabled() || IsHostLearningEnabled();
-}
-
-bool ResourcePrefetchPredictorConfig::IsPrefetchingEnabled() const {
-  return IsURLPrefetchingEnabled() || IsHostPrefetchingEnabled();
-}
-
-bool ResourcePrefetchPredictorConfig::IsURLLearningEnabled() const {
-  return (mode & URL_LEARNING) > 0;
-}
-
-bool ResourcePrefetchPredictorConfig::IsHostLearningEnabled() const {
-  return (mode & HOST_LEARNING) > 0;
-}
-
-bool ResourcePrefetchPredictorConfig::IsURLPrefetchingEnabled() const {
-  return (mode & URL_PREFETCHING) > 0;
-}
-
-bool ResourcePrefetchPredictorConfig::IsHostPrefetchingEnabled() const {
-  return (mode & HOST_PRFETCHING) > 0;
-}
-
-}  // namespace predictors