Add ReloadPageLoadMetricsObserver to have a metrics variant for reloads

chrome/browser/page_load_metrics/observers/reload_page_load_metrics_observer.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 CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_RELOAD_PAGE_LOAD_METRICS_OBSERVER_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_RELOAD_PAGE_LOAD_METRICS_OBSERVER_H_
+
+#include "base/macros.h"
+#include "components/page_load_metrics/browser/page_load_metrics_observer.h"
+
+namespace chrome {
+
+// An observer class to report metrics on pages those loading were initiated
+// by one of reload operations including hitting enter in the omnibox.
+// This ignore JavaScript-initiated loadings by location.reload() or
+// history.go(0).
+class ReloadPageLoadMetricsObserver
+    : public page_load_metrics::PageLoadMetricsObserver {
+ public:
+  ReloadPageLoadMetricsObserver();
+
+  // page_load_metrics::PageLoadMetricsObserver implementation:
+  void OnCommit(content::NavigationHandle* navigation_handle) override;
+  void OnFirstContentfulPaint(
+      const page_load_metrics::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& extra_info) override;
+
+ private:
+  bool page_transition_was_reload_;
+  bool initiated_by_user_gesture_;
+
+  DISALLOW_COPY_AND_ASSIGN(ReloadPageLoadMetricsObserver);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_RELOAD_PAGE_LOAD_METRICS_OBSERVER_H_