Add support for logging additional metrics in UKM.

chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h b/chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h
index 437d5c9a6df56d6bf610f1e75ce3f6b2dfd0e894..fd89cec2e7cf4d17f9ef10da1cf0e42cfe780242 100644
--- a/chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h
@@ -7,6 +7,7 @@
 
 #include "base/macros.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
+#include "components/ukm/ukm_source.h"
 
 // If URL-Keyed-Metrics (UKM) is enabled in the system, this is used to
 // populate it with top-level page-load metrics.
@@ -18,6 +19,7 @@ class UkmPageLoadMetricsObserver
   CreateIfNeeded();
 
   UkmPageLoadMetricsObserver();
+  ~UkmPageLoadMetricsObserver() override;
 
   // page_load_metrics::PageLoadMetricsObserver implementation:
   ObservePolicy OnStart(content::NavigationHandle* navigation_handle,
@@ -32,12 +34,21 @@ class UkmPageLoadMetricsObserver
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& info) override;
 
+  void OnFailedProvisionalLoad(
+      const page_load_metrics::FailedProvisionalLoadInfo& failed_load_info,
+      const page_load_metrics::PageLoadExtraInfo& extra_info) override;
+
   void OnComplete(const page_load_metrics::PageLoadTiming& timing,
                   const page_load_metrics::PageLoadExtraInfo& info) override;
 
  private:
-  void SendMetricsToUkm(const page_load_metrics::PageLoadTiming& timing,
-                        const page_load_metrics::PageLoadExtraInfo& info);
+  void PopulateTiming(const page_load_metrics::PageLoadTiming& timing);
+  void PopulatePageLoadExtraInfo(
+      const page_load_metrics::PageLoadExtraInfo& info);
+  void SendMetricsToUkm();
+
+  base::TimeTicks navigation_start_;
+  std::unique_ptr<ukm::UkmSource> source_;
 
   DISALLOW_COPY_AND_ASSIGN(UkmPageLoadMetricsObserver);
 };