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

third_party/WebKit/Source/core/timing/PerformanceNavigationTiming.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 PerformanceNavigationTiming_h
 #define PerformanceNavigationTiming_h
 
 #include "core/CoreExport.h"
 #include "core/dom/DOMHighResTimeStamp.h"
+#include "core/loader/FrameLoaderTypes.h"
 #include "core/timing/PerformanceResourceTiming.h"
 
 namespace blink {
 
+class Document;
+class DocumentTiming;
+class DocumentLoader;
+class DocumentLoadTiming;
+class LocalFrame;
+class ExecutionContext;
+class ResourceTimingInfo;
+class ResourceLoadTiming;
+
 class CORE_EXPORT PerformanceNavigationTiming final
     : public PerformanceResourceTiming {
   DEFINE_WRAPPERTYPEINFO();
+  friend class PerformanceNavigationTimingTest;
 
  public:
-  enum class NavigationType { Navigate, Reload, BackForward, Prerender };
+  PerformanceNavigationTiming(LocalFrame*,
+                              ResourceTimingInfo*,
+                              double timeOrigin);
 
-  PerformanceNavigationTiming(double timeOrigin,
-                              const String& requestedUrl,
-                              double unloadEventStart,
-                              double unloadEventEnd,
-                              double loadEventStart,
-                              double loadEventEnd,
-                              unsigned short redirectCount,
-                              double domInteractive,
-                              double domContentLoadedEventStart,
-                              double domContentLoadedEventEnd,
-                              double domComplete,
-                              NavigationType,
-                              double redirectStart,
-                              double redirectEnd,
-                              double fetchStart,
-                              double responseEnd,
-                              bool allowRedirectDetails,
-                              bool hasSameOriginAsPreviousDocument,
-                              ResourceLoadTiming*,
-                              double lastRedirectEndTime,
-                              double finishTime,
-                              unsigned long long transferSize,
-                              unsigned long long encodedBodyLength,
-                              unsigned long long decodedBodyLength,
-                              bool didReuseConnection);
+  // Attributes inheritted from PerformanceEntry.
+  DOMHighResTimeStamp duration() const override;
 
+  AtomicString initiatorType() const override;
+
+  // PerformanceNavigationTiming's unique attributes.
   DOMHighResTimeStamp unloadEventStart() const;
   DOMHighResTimeStamp unloadEventEnd() const;
   DOMHighResTimeStamp domInteractive() const;
   DOMHighResTimeStamp domContentLoadedEventStart() const;
   DOMHighResTimeStamp domContentLoadedEventEnd() const;
   DOMHighResTimeStamp domComplete() const;
   DOMHighResTimeStamp loadEventStart() const;
   DOMHighResTimeStamp loadEventEnd() const;
   AtomicString type() const;
   unsigned short redirectCount() const;
 
   // PerformanceResourceTiming overrides:
   DOMHighResTimeStamp fetchStart() const override;
   DOMHighResTimeStamp redirectStart() const override;
   DOMHighResTimeStamp redirectEnd() const override;
   DOMHighResTimeStamp responseEnd() const override;
 
+  DECLARE_VIRTUAL_TRACE();
+
  protected:
   void buildJSONValue(V8ObjectBuilder&) const override;
 
  private:
   ~PerformanceNavigationTiming() override;
 
+  static AtomicString getNavigationType(NavigationType, const Document*);
+  const DocumentTiming* documentTiming() const;
+  DocumentLoader* documentLoader() const;
+  DocumentLoadTiming* documentLoadTiming() const;
+
+  virtual ResourceLoadTiming* resourceLoadTiming() const;
+  virtual bool allowTimingDetails() const;
+  virtual bool didReuseConnection() const;
+  virtual unsigned long long getTransferSize() const;
+  virtual unsigned long long getEncodedBodySize() const;
+  virtual unsigned long long getDecodedBodySize() const;
+
+  bool getAllowRedirectDetails() const;
+
   double m_timeOrigin;
-  double m_unloadEventStart;
-  double m_unloadEventEnd;
-  double m_loadEventStart;
-  double m_loadEventEnd;
-  unsigned short m_redirectCount;
-  double m_domInteractive;
-  double m_domContentLoadedEventStart;
-  double m_domContentLoadedEventEnd;
-  double m_domComplete;
-  NavigationType m_type;
-  double m_redirectStart;
-  double m_redirectEnd;
-  double m_fetchStart;
-  double m_responseEnd;
-  bool m_allowRedirectDetails;
-  bool m_hasSameOriginAsPreviousDocument;
+  RefPtr<ResourceTimingInfo> m_resourceTimingInfo;
+  WeakMember<LocalFrame> m_frame;

[haraken, 2017/03/14 20:10:40]

I guess this should just be a Member.

Is there any reason you need to make it weak? i.e., does
PerformanceNavigationTiming outlive LocalFrame?

[sunjian, 2017/03/14 23:59:53]

I guess i wasn't taking who outlives whom into consideration.
PerformanceNavigationTiming only references LocalFrame for information but not
meant to be an owner of a LocalFrame which entails getting involved in the
life-cycle of LocalFrame. Correct me if i'm wrong about this please!

 };
 }  // namespace blink
 
 #endif  // PerformanceNavigationTiming_h