components/previews/core/previews_decider.h

// Copyright 2016 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 COMPONENTS_PREVIEWS_CORE_PREVIEWS_DECIDER_H_
#define COMPONENTS_PREVIEWS_CORE_PREVIEWS_DECIDER_H_
#include <string>
#include <vector>

#include "base/strings/string_piece.h"
#include "components/previews/core/previews_experiments.h"
#include "net/nqe/effective_connection_type.h"

class GURL;

namespace previews {
class PreviewsUserData;

class PreviewsDecider {
 public:
  // Whether |url| is allowed to show a preview of |type| as can be determined
  // at the start of a navigation (or start of a redirection). This can be
  // further checked at navigation commit time via |ShouldCommitPreview|.
  // Some types of previews will be checked for an applicable network quality
  // threshold - these are client previews that do not have optimization hint
  // support. Previews with optimization hint support can have variable
  // network quality thresholds based on the committed URL. Data Reduction
  // Proxy previews (i.e., LITE_PAGE) perform a network quality check on the
  // server.
  virtual bool ShouldAllowPreviewAtNavigationStart(
      PreviewsUserData* previews_data,
      const GURL& url,
      bool is_reload,
      PreviewsType type) const = 0;

  // Whether the |committed_url| is allowed to show a preview of |type|.
  virtual bool ShouldCommitPreview(PreviewsUserData* previews_data,
                                   const GURL& committed_url,
                                   PreviewsType type) const = 0;

  // Requests that any applicable detailed resource hints be loaded.
  virtual void LoadResourceHints(const GURL& url) = 0;

  // Logs UMA for whether the OptimizationGuide HintCache has a matching Hint
  // guidance for |url|. This is useful for measuring the effectiveness of the
  // page hints provided by Cacao.
  virtual void LogHintCacheMatch(const GURL& url, bool is_committed) const = 0;

 protected:
  PreviewsDecider() {}
  virtual ~PreviewsDecider() {}
};

}  // namespace previews

#endif  // COMPONENTS_PREVIEWS_CORE_PREVIEWS_DECIDER_H_