Add support for counting same-document AMP loads.

chrome/browser/page_load_metrics/observers/amp_page_load_metrics_observer.h

 // Copyright 2016 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_AMP_PAGE_LOAD_METRICS_OBSERVER_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_AMP_PAGE_LOAD_METRICS_OBSERVER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 
@@ skipping 13 matching lines @@
 // cache page will be tracked. Refreshing an AMP page served from google.com
 // will be tracked.
 class AMPPageLoadMetricsObserver
     : public page_load_metrics::PageLoadMetricsObserver {
  public:
   enum class AMPViewType {
     NONE,
     AMP_CACHE,
     GOOGLE_SEARCH_AMP_VIEWER,
     GOOGLE_NEWS_AMP_VIEWER,
+
+    // New values should be added before this final entry.
+    AMP_VIEW_TYPE_LAST
   };
 
   static AMPViewType GetAMPViewType(const GURL& url);
 
   AMPPageLoadMetricsObserver();
   ~AMPPageLoadMetricsObserver() override;
 
   // page_load_metrics::PageLoadMetricsObserver:
   ObservePolicy OnCommit(content::NavigationHandle* navigation_handle) override;
+  void OnCommitSameDocumentNavigation(
+      content::NavigationHandle* navigation_handle) override;
   void OnDomContentLoadedEventStart(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& info) override;
   void OnLoadEventStart(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& info) override;
   void OnFirstLayout(const page_load_metrics::PageLoadTiming& timing,
                      const page_load_metrics::PageLoadExtraInfo& info) override;
   void OnFirstContentfulPaintInPage(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& info) override;
   void OnParseStart(const page_load_metrics::PageLoadTiming& timing,
                     const page_load_metrics::PageLoadExtraInfo& info) override;
 
  private:
+  GURL committed_url_;
+  GURL last_same_document_url_;
   AMPViewType view_type_ = AMPViewType::NONE;
 
   DISALLOW_COPY_AND_ASSIGN(AMPPageLoadMetricsObserver);
 };
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_AMP_PAGE_LOAD_METRICS_OBSERVER_H_