[PageLoadMetrics] Don't record an ads histogram if the page hasn't committed

chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.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_PAGE_LOAD_METRICS_OBSERVER_TEST_HARNESS_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_PAGE_LOAD_METRICS_OBSERVER_TEST_HARNESS_H_
 
 #include "base/macros.h"
 #include "base/test/histogram_tester.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
@@ skipping 55 matching lines @@
   void SimulateInputEvent(const blink::WebInputEvent& event);
 
   // Simulates the app being backgrounded.
   void SimulateAppEnterBackground();
 
   // Simulate playing a media element.
   void SimulateMediaPlayed();
 
   const base::HistogramTester& histogram_tester() const;
 
+  MetricsWebContentsObserver* observer() const;
+
   // Gets the PageLoadExtraInfo for the committed_load_ in observer_.
   const PageLoadExtraInfo GetPageLoadExtraInfoForCommittedLoad();
 
  private:
   base::HistogramTester histogram_tester_;
   MetricsWebContentsObserver* observer_;
 
   DISALLOW_COPY_AND_ASSIGN(PageLoadMetricsObserverTestHarness);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_PAGE_LOAD_METRICS_OBSERVER_TEST_HARNESS_H_