predictors: Introduce GlowplugPredictor.

chrome/browser/predictors/glowplug_config.h

+// Copyright 2017 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.
+
+#ifndef CHROME_BROWSER_PREDICTORS_GLOWPLUG_CONFIG_H_
+#define CHROME_BROWSER_PREDICTORS_GLOWPLUG_CONFIG_H_
+
+#include <cstddef>
+
+class Profile;
+
+namespace predictors {
+
+struct GlowplugPredictorConfig;
+
+// Returns whether glowplug is enabled, and populate |config|, if not nullptr.

[alexilin, 2017/05/12 14:26:45]

nit:
/populate/populates

[Benoit L, 2017/05/12 15:13:11]

Done.

+bool IsGlowplugEnabled(Profile* profile, GlowplugPredictorConfig* config);
+
+// Indicates what caused the page load hint.
+enum class HintOrigin { NAVIGATION, EXTERNAL };
+
+// Represents the config for the Glowplug predictor.
+struct GlowplugPredictorConfig {
+  // Initializes the config with default values.
+  GlowplugPredictorConfig();
+  GlowplugPredictorConfig(const GlowplugPredictorConfig& other);
+  ~GlowplugPredictorConfig();
+
+  // The mode the prefetcher is running in. Forms a bit map.
+  enum Mode {
+    LEARNING = 1 << 0,
+    PREFETCHING_FOR_NAVIGATION = 1 << 2,  // Should also turn on LEARNING.
+    PREFETCHING_FOR_EXTERNAL = 1 << 3     // Should also turn on LEARNING.
+  };
+  int mode;
+
+  // Helpers to deal with mode.
+  bool IsLearningEnabled() const;
+  bool IsPrefetchingEnabledForSomeOrigin(Profile* profile) const;
+  bool IsPrefetchingEnabledForOrigin(Profile* profile, HintOrigin origin) const;
+
+  bool IsLowConfidenceForTest() const;
+  bool IsHighConfidenceForTest() const;
+  bool IsMoreResourcesEnabledForTest() const;
+  bool IsSmallDBEnabledForTest() const;
+
+  // If a navigation hasn't seen a load complete event in this much time, it
+  // is considered abandoned.
+  size_t max_navigation_lifetime_seconds;
+
+  // Size of LRU caches for the URL and host data.
+  size_t max_urls_to_track;
+  size_t max_hosts_to_track;
+
+  // The number of times we should have seen a visit to this URL in history
+  // to start tracking it. This is to ensure we don't bother with oneoff
+  // entries. For hosts we track each one.
+  size_t min_url_visit_count;
+
+  // The maximum number of resources to store per entry.
+  size_t max_resources_per_entry;
+  // The maximum number of origins to store per entry.
+  size_t max_origins_per_entry;
+  // The number of consecutive misses after which we stop tracking a resource
+  // URL.
+  size_t max_consecutive_misses;
+  // The number of consecutive misses after which we stop tracking a redirect
+  // endpoint.
+  size_t max_redirect_consecutive_misses;
+
+  // The minimum confidence (accuracy of hits) required for a resource to be
+  // prefetched.
+  float min_resource_confidence_to_trigger_prefetch;
+  // The minimum number of times we must have a URL on record to prefetch it.
+  size_t min_resource_hits_to_trigger_prefetch;
+
+  // Maximum number of prefetches that can be inflight for a single navigation.
+  size_t max_prefetches_inflight_per_navigation;
+  // Maximum number of prefetches that can be inflight for a host for a single
+  // navigation.
+  size_t max_prefetches_inflight_per_host_per_navigation;
+  // True iff the predictor could use a url-based database.
+  bool is_url_learning_enabled;
+  // True iff the predictor could use manifests.
+  bool is_manifests_enabled;
+  // True iff origin-based learning is enabled.
+  bool is_origin_learning_enabled;
+};
+
+}  // namespace predictors
+
+#endif  // CHROME_BROWSER_PREDICTORS_GLOWPLUG_CONFIG_H_