Tracing for NavigationHandle lifetime and state.

chrome/browser/page_load_metrics/experiments/delay_navigation_throttle.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_EXPERIMENTS_DELAY_NAVIGATION_THROTTLE_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_EXPERIMENTS_DELAY_NAVIGATION_THROTTLE_H_
 
 #include <memory>
 
 #include "base/feature_list.h"
@@ skipping 35 matching lines @@
   DelayNavigationThrottle(content::NavigationHandle* handle,
                           scoped_refptr<base::TaskRunner> task_runner,
                           base::TimeDelta navigation_delay);
   ~DelayNavigationThrottle() override;
 
   // Return the navigation delay for this throttle.
   base::TimeDelta navigation_delay() const { return navigation_delay_; }
 
   // content::NavigationThrottle:
   content::NavigationThrottle::ThrottleCheckResult WillStartRequest() override;
+  const char* GetNameForLogging() override;
 
  private:
   void OnDelayComplete();
 
   const scoped_refptr<base::TaskRunner> task_runner_;
   const base::TimeDelta navigation_delay_;
 
   // The time we added a delay to this navigation.
   base::TimeTicks delay_start_time_;
 
   // This has to be the last member of the class.
   base::WeakPtrFactory<DelayNavigationThrottle> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DelayNavigationThrottle);
 };
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_EXPERIMENTS_DELAY_NAVIGATION_THROTTLE_H_