ServiceWorker: Keep the worker alive until FetchEvent.waitUntil settles

third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h

Index: third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h
diff --git a/third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h b/third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h
index ac398952d5c389032b0ac3a65e3397a011d0ae32..53187cbe8e03b072fd6eb4a1f6a7543d59bca06e 100644
--- a/third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h
+++ b/third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h
@@ -25,6 +25,7 @@ class MODULES_EXPORT WaitUntilObserver final : public GarbageCollectedFinalized<
 public:
     enum EventType {
         Activate,
+        Fetch,
         Install,
         Message,
         NotificationClick,
@@ -43,6 +44,12 @@ public:
     // the given promise is resolved or rejected.
     void waitUntil(ScriptState*, ScriptPromise, ExceptionState&);
 
+    // These methods can be called when the lifecycle of ExtendableEvent
+    // observed by this WaitUntilObserver should be extended by other reason
+    // than ExtendableEvent.waitUntil.
+    void incrementPendingActivity();
+    void decrementPendingActivity();
+
     DECLARE_VIRTUAL_TRACE();
 
 private:
@@ -53,9 +60,6 @@ private:
 
     void reportError(const ScriptValue&);
 
-    void incrementPendingActivity();
-    void decrementPendingActivity();
-
     void consumeWindowInteraction(Timer<WaitUntilObserver>*);
 
     EventType m_type;