Adding previews information to PLM UKM

chrome/browser/page_load_metrics/observers/previews_ukm_observer.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_PAGE_LOAD_METRICS_OBSERVERS_PREVIEWS_UKM_OBSERVER_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_PREVIEWS_UKM_OBSERVER_H_
+
+#include "base/macros.h"
+#include "base/sequence_checker.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
+
+namespace content {
+class NavigationHandle;
+}
+
+namespace previews {
+
+// Observer responsible for appending previews information to the PLM UKM
+// report.
+class PreviewsUKMObserver : public page_load_metrics::PageLoadMetricsObserver {
+ public:
+  PreviewsUKMObserver();
+  ~PreviewsUKMObserver() override;
+
+  // page_load_metrics::PageLoadMetricsObserver:
+  ObservePolicy OnStart(content::NavigationHandle* navigation_handle,
+                        const GURL& currently_committed_url,
+                        bool started_in_foreground) override;
+  ObservePolicy OnCommit(content::NavigationHandle* navigation_handle,
+                         ukm::SourceId source_id) override;
+  ObservePolicy FlushMetricsOnAppEnterBackground(
+      const page_load_metrics::mojom::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& info) override;
+  void OnComplete(const page_load_metrics::mojom::PageLoadTiming& timing,
+                  const page_load_metrics::PageLoadExtraInfo& info) override;
+  void OnLoadedResource(const page_load_metrics::ExtraRequestCompleteInfo&
+                            extra_request_complete_info) override;
+  void OnEventOccurred(const void* const event_key) override;
+
+ private:
+  void RecordPreviewsTypes(const page_load_metrics::PageLoadExtraInfo& info);
+
+  bool server_lofi_seen_ = false;
+  bool client_lofi_seen_ = false;
+  bool lite_page_seen_ = false;
+  bool opt_out_occurred_ = false;
+
+  SEQUENCE_CHECKER(sequence_checker_);
+
+  DISALLOW_COPY_AND_ASSIGN(PreviewsUKMObserver);
+};
+
+}  // namespace previews
+
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_PREVIEWS_UKM_OBSERVER_H_