chrome/browser/resource_coordinator/local_site_characteristics_webcontents_observer.h

// Copyright 2018 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_RESOURCE_COORDINATOR_LOCAL_SITE_CHARACTERISTICS_WEBCONTENTS_OBSERVER_H_
#define CHROME_BROWSER_RESOURCE_COORDINATOR_LOCAL_SITE_CHARACTERISTICS_WEBCONTENTS_OBSERVER_H_

#include "base/macros.h"
#include "base/sequence_checker.h"
#include "base/time/time.h"
#include "chrome/browser/resource_coordinator/local_site_characteristics_data_writer.h"
#include "chrome/browser/resource_coordinator/tab_load_tracker.h"
#include "content/public/browser/visibility.h"
#include "content/public/browser/web_contents_observer.h"
#include "url/origin.h"

namespace content {
class NavigationHandle;
}

namespace performance_manager {
class PerformanceManager;
}

namespace resource_coordinator {

// WebContents observer that manages a SiteCharacteristicsDataWriter associated
// with a WebContents and forwards the appropriate events to it.
class LocalSiteCharacteristicsWebContentsObserver
    : public content::WebContentsObserver,
      public TabLoadTracker::Observer {
 public:
  explicit LocalSiteCharacteristicsWebContentsObserver(
      content::WebContents* contents);
  ~LocalSiteCharacteristicsWebContentsObserver() override;

  // Call once before an instance of this class is created.
  static void MaybeCreateGraphObserver();

  // WebContentsObserver implementation.
  void OnVisibilityChanged(content::Visibility visibility) override;
  void WebContentsDestroyed() override;
  void DidFinishNavigation(
      content::NavigationHandle* navigation_handle) override;
  void TitleWasSet(content::NavigationEntry* entry) override;
  void DidUpdateFaviconURL(
      const std::vector<content::FaviconURL>& candidates) override;
  void OnAudioStateChanged(bool audible) override;

  // GraphObserver notifications public for testing.
  void OnNonPersistentNotificationCreated();

  // TabLoadTracker::Observer:
  void OnLoadingStateChange(content::WebContents* web_contents,
                            LoadingState old_loading_state,
                            LoadingState new_loading_state) override;


  SiteCharacteristicsDataWriter* GetWriterForTesting() const {
    return writer_.get();
  }
  url::Origin GetWriterOriginForTesting() const { return writer_origin_; }
  void ResetWriterForTesting() { writer_.reset(); }

 private:
  // A simple observer on the performance manager graph to get notifications of
  // events in the graph.
  class GraphObserver;

  enum class FeatureType {
    kTitleChange,
    kFaviconChange,
    kAudioUsage,
    kNotificationUsage,
  };

  // Indicates if the feature usage event just received should be ignored.
  bool ShouldIgnoreFeatureUsageEvent(FeatureType feature_type);

  // Helper function to maybe notify |writer_| that a feature event has been
  // received while in background. Doesn't do anything if
  // ShouldIgnoreFeatureUsageEvent returns true.
  void MaybeNotifyBackgroundFeatureUsage(
      void (SiteCharacteristicsDataWriter::*method)(),
      FeatureType feature_type);

  // Function to call when the site switch to the loaded state.
  void OnSiteLoaded();

  // Updates |backgrounded_time_| based on |visibility|.
  void UpdateBackgroundedTime(performance_manager::TabVisibility visibility);

  // The writer that processes the event received by this class.
  std::unique_ptr<SiteCharacteristicsDataWriter> writer_;

  // The Origin tracked by the writer.
  url::Origin writer_origin_;

  // Favicon and title are set when a page is loaded, we only want to send
  // signals to the database about title and favicon update from the previous
  // title and favicon, thus we want to ignore the very first update since it is
  // always supposed to happen.
  bool first_time_favicon_set_ = false;
  bool first_time_title_set_ = false;

  performance_manager::PerformanceManager* performance_manager_ = nullptr;

  // The time at which this tab switched to the loaded state, null if this tab
  // is not currently loaded.
  base::TimeTicks loaded_time_;

  // The time at which this tab has been backgrounded, null if this tab is
  // currently visible.
  base::TimeTicks backgrounded_time_;

  SEQUENCE_CHECKER(sequence_checker_);

  DISALLOW_COPY_AND_ASSIGN(LocalSiteCharacteristicsWebContentsObserver);
};

}  // namespace resource_coordinator

#endif  // CHROME_BROWSER_RESOURCE_COORDINATOR_LOCAL_SITE_CHARACTERISTICS_WEBCONTENTS_OBSERVER_H_