Optional <TimeDelta> since they may be non existent.

components/page_load_metrics/browser/page_load_metrics_util.cc

 // 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.
 
 #include "components/page_load_metrics/browser/page_load_metrics_util.h"
 
 #include <algorithm>
 
 #include "components/page_load_metrics/browser/page_load_metrics_observer.h"
 #include "components/page_load_metrics/common/page_load_timing.h"
 
 namespace page_load_metrics {
 
-bool WasStartedInForegroundEventInForeground(base::TimeDelta event,
+bool WasStartedInForegroundEventInForeground(const base::TimeDelta& event,
                                              const PageLoadExtraInfo& info) {
   return info.started_in_foreground && !event.is_zero() &&
-         (info.first_background_time.is_zero() ||
-          event < info.first_background_time);
+         (!info.first_background_time ||
+          event < info.first_background_time.value());
+}
+
+bool WasStartedInForegroundOptionalEventInForeground(
+    const base::Optional<base::TimeDelta>& event,
+    const PageLoadExtraInfo& info) {
+  return info.started_in_foreground && event &&

[Bryan McQuade, 2016/03/29 18:33:43]

could this become:
return event && WasStartedInForegroundEventInForeground(event.value(), info);

[shivanisha, 2016/03/29 18:54:25]

Since WasStartedInForegroundEventInForeground is returning false if
event.is_zero() is true, it will be an anti-pattern to this fix.

[Bryan McQuade, 2016/03/29 19:00:47]

Ah, I missed that. Good catch. Thanks!

+         (!info.first_background_time ||
+          event.value() < info.first_background_time.value());
 }
 
 }  // namespace page_load_metrics