Introduce ServiceWorker.EventDispatchingDelay UMA

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

 // Copyright 2014 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 RespondWithObserver_h
 #define RespondWithObserver_h
 
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/events/EventTarget.h"
 #include "modules/ModulesExport.h"
@@ skipping 14 matching lines @@
 // notifies the client.
 class MODULES_EXPORT RespondWithObserver : public GarbageCollectedFinalized<RespondWithObserver>, public ContextLifecycleObserver {
     USING_GARBAGE_COLLECTED_MIXIN(RespondWithObserver);
 public:
     virtual ~RespondWithObserver();
 
     static RespondWithObserver* create(ExecutionContext*, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode, WebURLRequest::FrameType, WebURLRequest::RequestContext, WaitUntilObserver*);
 
     void contextDestroyed() override;
 
+    void willDispatchEvent();
     void didDispatchEvent(DispatchEventResult dispatchResult);
 
     // Observes the promise and delays calling didHandleFetchEvent() until the
     // given promise is resolved or rejected.
     void respondWith(ScriptState*, ScriptPromise, ExceptionState&);
 
     void responseWasRejected(WebServiceWorkerResponseError);
     virtual void responseWasFulfilled(const ScriptValue&);
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     RespondWithObserver(ExecutionContext*, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode, WebURLRequest::FrameType, WebURLRequest::RequestContext, WaitUntilObserver*);
 
 private:
     class ThenFunction;
 
     int m_eventID;
     KURL m_requestURL;
     WebURLRequest::FetchRequestMode m_requestMode;
     WebURLRequest::FrameType m_frameType;
     WebURLRequest::RequestContext m_requestContext;
 
+    double m_eventDispatchTime = 0;
+
     enum State { Initial, Pending, Done };
     State m_state;
 
     // RespondWith should ensure the ExtendableEvent is alive until the promise
     // passed to RespondWith is resolved. The lifecycle of the ExtendableEvent
     // is controlled by WaitUntilObserver, so not only
     // WaitUntilObserver::ThenFunction but RespondWith needs to have a strong
     // reference to the WaitUntilObserver.
     Member<WaitUntilObserver> m_observer;
 };
 
 } // namespace blink
 
 #endif // RespondWithObserver_h