Update PageLoadTiming to use base::Optional

components/page_load_metrics/browser/page_load_metrics_util.h

 // Copyright 2015 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_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_UTIL_H_
 #define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_UTIL_H_
 
 #include "base/metrics/histogram_macros.h"
 #include "base/optional.h"
 #include "base/time/time.h"
@@ skipping 22 matching lines @@
                                              const PageLoadExtraInfo& info);
 
 bool WasStartedInForegroundOptionalEventInForeground(
     const base::Optional<base::TimeDelta>& event,
     const PageLoadExtraInfo& info);
 
 // Returns true if:
 // - Parse started and did not complete but the entire page load duration
 // happened in the foreground.
 // - Parse completed and happened entirely in the foreground.
-bool WasParseInForeground(base::TimeDelta parse_start,
-                          base::TimeDelta parse_stop,
+bool WasParseInForeground(const base::Optional<base::TimeDelta>& parse_start,
+                          const base::Optional<base::TimeDelta>& parse_stop,
                           const PageLoadExtraInfo& info);
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_UTIL_H_