Fix PerformanceNavigationTiming accessor behavior after document detach.

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/ContextLifecycleObserver.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 {
+    : public PerformanceResourceTiming,
+      public ContextClient {
   DEFINE_WRAPPERTYPEINFO();
+  USING_GARBAGE_COLLECTED_MIXIN(PerformanceNavigationTiming);
   friend class PerformanceNavigationTimingTest;
 
  public:
   enum class NavigationType { Navigate, Reload, BackForward, Prerender };
 
   PerformanceNavigationTiming(LocalFrame*,
                               ResourceTimingInfo*,
                               double timeOrigin);
 
   // Attributes inheritted from PerformanceEntry.
@@ skipping 35 matching lines @@
   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;
   RefPtr<ResourceTimingInfo> m_resourceTimingInfo;
-  // TODO(sunjian): Investigate why not using a Member instead.
-  WeakMember<LocalFrame> m_frame;
 };
 }  // namespace blink
 
 #endif  // PerformanceNavigationTiming_h