predictors: Introduce GlowplugPredictor.

chrome/browser/predictors/glowplug_config.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// 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_RESOURCE_PREFETCH_COMMON_H_
-#define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_COMMON_H_
+#ifndef CHROME_BROWSER_PREDICTORS_GLOWPLUG_CONFIG_H_
+#define CHROME_BROWSER_PREDICTORS_GLOWPLUG_CONFIG_H_
 
-#include <stddef.h>
-
-#include "base/feature_list.h"
-#include "base/time/time.h"
-#include "components/sessions/core/session_id.h"
-#include "url/gurl.h"
+#include <cstddef>
 
 class Profile;
 
-namespace content {
-class WebContents;
-}
-
 namespace predictors {
 
-extern const char kSpeculativeResourcePrefetchingFeatureName[];
-extern const char kModeParamName[];
-extern const char kLearningMode[];
-extern const char kExternalPrefetchingMode[];
-extern const char kPrefetchingMode[];
-extern const char kEnableUrlLearningParamName[];
-extern const char kEnableManifestsParamName[];
-extern const char kEnableOriginLearningParamName[];
-extern const base::Feature kSpeculativeResourcePrefetchingFeature;
+struct GlowplugPredictorConfig;
 
-struct ResourcePrefetchPredictorConfig;
-
-// Returns true if prefetching is enabled. And will initilize the |config|
-// fields to the appropritate values.
-bool IsSpeculativeResourcePrefetchingEnabled(
-    Profile* profile,
-    ResourcePrefetchPredictorConfig* config);
-
-// Represents the type of key based on which prefetch data is stored.
-enum PrefetchKeyType {
-  PREFETCH_KEY_TYPE_HOST,
-  PREFETCH_KEY_TYPE_URL
-};
+// Returns whether glowplug is enabled, and populate |config|, if not nullptr.
+bool IsGlowplugEnabled(Profile* profile, GlowplugPredictorConfig* config);
 
 // Indicates what caused the prefetch request.
 enum class PrefetchOrigin { NAVIGATION, EXTERNAL };
 
-// Represents a single navigation for a render frame.
-struct NavigationID {
-  NavigationID();
-  explicit NavigationID(content::WebContents* web_contents);
-  NavigationID(content::WebContents* web_contents,
-               const GURL& main_frame_url,
-               const base::TimeTicks& creation_time);
-  NavigationID(const NavigationID& other);
-
-  bool operator<(const NavigationID& rhs) const;
-  bool operator==(const NavigationID& rhs) const;
-
-  // Returns true iff the tab_id is valid and the Main frame URL is set.
-  bool is_valid() const;
-
-  SessionID::id_type tab_id;
-  GURL main_frame_url;
-
-  // NOTE: Even though we store the creation time here, it is not used during
-  // comparison of two NavigationIDs because it cannot always be determined
-  // correctly.
-  base::TimeTicks creation_time;
-};
-
-// Represents the config for the resource prefetch prediction algorithm.
-struct ResourcePrefetchPredictorConfig {
+// Represents the config for the Glowplug predictor.
+struct GlowplugPredictorConfig {

[alexilin, 2017/05/11 16:53:12]

I don't see clear benefits of moving it outside of resource_prefetch_common.
What is the goal here?

Do we want to have one big config for the whole glowplug or separate configs for
each component?

[Benoit L, 2017/05/12 12:12:52]

The goal is to have a global object to configure glowplug, with members for the
various components. Part of the config will be shared, for instance  how many
hosts to keep, confidence levels, etc. So it makes sense to have a
glowplug-level config, containing everything for now.

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

Cool, makes sense. Thanks!

   // Initializes the config with default values.
-  ResourcePrefetchPredictorConfig();
-  ResourcePrefetchPredictorConfig(const ResourcePrefetchPredictorConfig& other);
-  ~ResourcePrefetchPredictorConfig();
+  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.
@@ skipping 45 matching lines @@
   // 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_RESOURCE_PREFETCH_COMMON_H_
+#endif  // CHROME_BROWSER_PREDICTORS_GLOWPLUG_CONFIG_H_