PageLoadMetricsObservers observe individual page loads

chrome/browser/page_load_metrics/observers/google_captcha_observer.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 CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_GOOGLE_CAPTCHA_OBSERVER_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_GOOGLE_CAPTCHA_OBSERVER_H_
 
 #include "base/macros.h"
 #include "components/page_load_metrics/browser/page_load_metrics_observer.h"
 
 namespace google_captcha_observer {
 
 // Returns true if the given URL matches a Google CAPTCHA page.
 bool IsGoogleCaptcha(const GURL& url);
 
 class GoogleCaptchaObserver
     : public page_load_metrics::PageLoadMetricsObserver {
  public:
-  explicit GoogleCaptchaObserver(
-      page_load_metrics::PageLoadMetricsObservable* metrics);
+  GoogleCaptchaObserver();
 
   // page_load_metrics::PageLoadMetricsObserver implementation:
   void OnCommit(content::NavigationHandle* navigation_handle) override;
   void OnRedirect(content::NavigationHandle* navigation_handle) override;
-  void OnPageLoadMetricsGoingAway() override;
 
  private:
   bool saw_solution_;
-  page_load_metrics::PageLoadMetricsObservable* const metrics_;
   DISALLOW_COPY_AND_ASSIGN(GoogleCaptchaObserver);
-
 };
 
 }  // namespace google_captcha_observer
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_GOOGLE_CAPTCHA_OBSERVER_H_