Hide PingLoader lifetime implementation detail from outside view.

third_party/WebKit/Source/core/loader/PingLoader.h

Index: third_party/WebKit/Source/core/loader/PingLoader.h
diff --git a/third_party/WebKit/Source/core/loader/PingLoader.h b/third_party/WebKit/Source/core/loader/PingLoader.h
index 3350441709737f56ad5cf8257f221a5ed973576d..056c3a5325ec9606b00a528e4568f5675d86fcef 100644
--- a/third_party/WebKit/Source/core/loader/PingLoader.h
+++ b/third_party/WebKit/Source/core/loader/PingLoader.h
@@ -57,7 +57,7 @@ class ResourceRequest;
 // The ping loader is used by audit pings, beacon transmissions and image loads
 // during page unloading.
 //
-class CORE_EXPORT PingLoader : public RefCountedGarbageCollected<PingLoader>, public LocalFrameLifecycleObserver, private WebURLLoaderClient {
+class CORE_EXPORT PingLoader : public GarbageCollectedFinalized<PingLoader>, public LocalFrameLifecycleObserver, private WebURLLoaderClient {
     USING_GARBAGE_COLLECTED_MIXIN(PingLoader);
     WTF_MAKE_NONCOPYABLE(PingLoader);
 public:
@@ -98,6 +98,7 @@ private:
     Timer<PingLoader> m_timeout;
     String m_url;
     unsigned long m_identifier;
+    SelfKeepAlive<PingLoader> m_keepAlive;
 };
 
 } // namespace blink