Report nav timing 2 instance as soon as it's requested.

third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.h

Index: third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.h
diff --git a/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.h b/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.h
index 49a1456172a361cbcf63a4852d7ebae3259d9d48..bf8d331851d3c3d37452335cec5b1c6a76c46d2b 100644
--- a/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.h
+++ b/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.h
@@ -142,7 +142,8 @@ class PLATFORM_EXPORT ResourceFetcher
   void reloadLoFiImages();
 
   // Calling this method before main document resource is fetched is invalid.
-  ResourceTimingInfo* getNavigationTimingInfo();
+  // This method should only be called once.
+  std::unique_ptr<ResourceTimingInfo> getNavigationTimingInfo();
 
   // This is only exposed for testing purposes.
   HeapListHashSet<Member<Resource>>* preloads() { return m_preloads.get(); }
@@ -234,6 +235,7 @@ class PLATFORM_EXPORT ResourceFetcher
   ResourceTimingInfoMap m_resourceTimingInfoMap;
 
   std::unique_ptr<ResourceTimingInfo> m_navigationTimingInfo;
+  ResourceTimingInfo* m_navigationTimingInfoRef;
 
   Vector<std::unique_ptr<ResourceTimingInfo>> m_scheduledResourceTimingReports;