Add support for counting same-document AMP loads.

chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.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_OBSERVERS_ADS_PAGE_LOAD_METRICS_OBSERVER_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_ADS_PAGE_LOAD_METRICS_OBSERVER_H_
 
 #include <list>
 #include <map>
 #include <memory>
 
 #include "base/macros.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 #include "net/http/http_response_info.h"
 
 // This observer labels each sub-frame as an ad or not, and keeps track of
 // relevant per-frame and whole-page byte statistics.
 class AdsPageLoadMetricsObserver
     : public page_load_metrics::PageLoadMetricsObserver {
  public:
   // Returns a new AdsPageLoadMetricObserver. If the feature is disabled it
   // returns nullptr.
   static std::unique_ptr<AdsPageLoadMetricsObserver> CreateIfNeeded();
 
   AdsPageLoadMetricsObserver();
   ~AdsPageLoadMetricsObserver() override;
 
   // page_load_metrics::PageLoadMetricsObserver
   ObservePolicy OnCommit(content::NavigationHandle* navigation_handle) override;
-  ObservePolicy OnDidFinishSubFrameNavigation(
+  void OnDidFinishSubFrameNavigation(
       content::NavigationHandle* navigation_handle) override;
   ObservePolicy FlushMetricsOnAppEnterBackground(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& extra_info) override;
   void OnLoadedResource(const page_load_metrics::ExtraRequestCompleteInfo&
                             extra_request_info) override;
   void OnComplete(const page_load_metrics::PageLoadTiming& timing,
                   const page_load_metrics::PageLoadExtraInfo& info) override;
 
  private:
@@ skipping 30 matching lines @@
   std::map<FrameTreeNodeId, page_load_metrics::ExtraRequestCompleteInfo>
       ongoing_navigation_resources_;
 
   size_t page_bytes_ = 0u;
   size_t uncached_page_bytes_ = 0u;
 
   DISALLOW_COPY_AND_ASSIGN(AdsPageLoadMetricsObserver);
 };
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_ADS_PAGE_LOAD_METRICS_OBSERVER_H_