Re-add resource speculative prefetching code

chrome/browser/predictors/resource_prefetch_common.cc

Index: chrome/browser/predictors/resource_prefetch_common.cc
diff --git a/chrome/browser/predictors/resource_prefetch_common.cc b/chrome/browser/predictors/resource_prefetch_common.cc
new file mode 100644
index 0000000000000000000000000000000000000000..731bda64f3922ff9c41f81c7ae561e1a5bea9c3a
--- /dev/null
+++ b/chrome/browser/predictors/resource_prefetch_common.cc
@@ -0,0 +1,245 @@
+// Copyright 2014 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_frame_id(-1) {
+}
+
+NavigationID::NavigationID(const NavigationID& other)
+    : render_process_id(other.render_process_id),
+      render_frame_id(other.render_frame_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_frame_id(web_contents->GetRenderViewHost()->GetRoutingID()),
+      main_frame_url(web_contents->GetURL()) {
+}
+
+bool NavigationID::is_valid() const {
+  return render_process_id != -1 && render_frame_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_frame_id != rhs.render_frame_id)
+    return render_frame_id < rhs.render_frame_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_frame_id == other.render_frame_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