[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.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 "chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h"
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
@@ skipping 169 matching lines @@
   content::RenderFrameHost* render_frame_host = web_contents()->GetMainFrame();
   observer_->MediaStartedPlaying(video_type,
                                  std::make_pair(render_frame_host, 0));
 }
 
 const base::HistogramTester&
 PageLoadMetricsObserverTestHarness::histogram_tester() const {
   return histogram_tester_;
 }
 
+MetricsWebContentsObserver* PageLoadMetricsObserverTestHarness::observer()
+    const {
+  return observer_;
+}
+
 const PageLoadExtraInfo
 PageLoadMetricsObserverTestHarness::GetPageLoadExtraInfoForCommittedLoad() {
   return observer_->GetPageLoadExtraInfoForCommittedLoad();
 }
 
 void PageLoadMetricsObserverTestHarness::NavigateWithPageTransitionAndCommit(
     const GURL& url,
     ui::PageTransition transition) {
   controller().LoadURL(url, content::Referrer(), transition, std::string());
   content::WebContentsTester::For(web_contents())->CommitPendingNavigation();
 }
 
 }  // namespace page_load_metrics