predictors: Introduce GlowplugPredictor.

chrome/browser/predictors/glowplug_predictor.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_PREDICTOR_H_
+#define CHROME_BROWSER_PREDICTORS_GLOWPLUG_PREDICTOR_H_
+
+#include <memory>
+
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/predictors/resource_prefetch_common.h"
+#include "chrome/browser/predictors/resource_prefetch_predictor.h"
+#include "components/keyed_service/core/keyed_service.h"
+
+class Profile;
+
+namespace predictors {
+
+class ResourcePrefetchPredictor;
+
+// Entry point for the Glowplug predictor.
+// From a high-level request (GURL and motivation) and a database of historical
+// data, initiates predictive actions to speed up page loads.
+//
+// See ResourcePrefetchPredictor for a description of the resource prefetch
+// predictor.
+//
+// All methods must be called from the UI thread.
+class GlowplugPredictor : public KeyedService,
+                          public base::SupportsWeakPtr<GlowplugPredictor> {
+ public:
+  GlowplugPredictor(const GlowplugPredictorConfig& config, Profile* profile);
+  ~GlowplugPredictor() override;
+
+  // Hints that a page load is expected for |url|, with the hint coming from a
+  // given |origin|. May trigger actions, such as prefetch and/or preconnect.
+  void PrepareForPageLoad(const GURL& url, HintOrigin origin);
+
+  // Indicates that a page load hint is no longer active.
+  void CancelPageLoadHint(const GURL& url);
+
+  // Don't use, internal only.
+  ResourcePrefetchPredictor* resource_prefetch_predictor() const;
+
+  // KeyedService methods override.

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

silly nit:
/KeyedService methods override./KeyedService:

My point is it would be nice to use the same style for marking overrides. During
refactoring, we could converge :)

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

Done.

+  void Shutdown() override;
+
+ private:
+  std::unique_ptr<ResourcePrefetchPredictor> resource_prefetch_predictor_;
+
+  DISALLOW_COPY_AND_ASSIGN(GlowplugPredictor);
+};
+
+}  // namespace predictors
+
+#endif  // CHROME_BROWSER_PREDICTORS_GLOWPLUG_PREDICTOR_H_