ServiceWorker: Keep the worker alive until FetchEvent.waitUntil settles

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

Index: third_party/WebKit/Source/modules/serviceworkers/RespondWithObserver.cpp
diff --git a/third_party/WebKit/Source/modules/serviceworkers/RespondWithObserver.cpp b/third_party/WebKit/Source/modules/serviceworkers/RespondWithObserver.cpp
index 5c0d70895f69dd01c532329342ff3e778281bed6..a482edc0ea5a53e9b02c62f391b6824b39b2e2a3 100644
--- a/third_party/WebKit/Source/modules/serviceworkers/RespondWithObserver.cpp
+++ b/third_party/WebKit/Source/modules/serviceworkers/RespondWithObserver.cpp
@@ -145,15 +145,19 @@ private:
 
 RespondWithObserver::~RespondWithObserver() {}
 
-RespondWithObserver* RespondWithObserver::create(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext)
+RespondWithObserver* RespondWithObserver::create(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext, WaitUntilObserver* observer)
 {
-    return new RespondWithObserver(context, eventID, requestURL, requestMode, frameType, requestContext);
+    return new RespondWithObserver(context, eventID, requestURL, requestMode, frameType, requestContext, observer);
 }
 
 void RespondWithObserver::contextDestroyed()
 {
     ContextLifecycleObserver::contextDestroyed();
     m_state = Done;
+    if (m_observer) {
+        m_observer->decrementPendingActivity();

[falken, 2016/06/22 01:27:32]

Where is the incrementPendingActivity this balances out? Are we sure it's
correct to decrement here?

[shimazu, 2016/06/22 05:41:27]

m_observer is non-null only when respondWith is in-flight at this point 
because didDispatchEvent decrements the counter and clears m_observer if there
is no respondWith, so this might be not a problem. 

Anyway, I found another bug; there is an excess decrementPendingActivity at the
last of didDispatchEvent... I removed it.

+        m_observer.clear();
+    }
 }
 
 void RespondWithObserver::didDispatchEvent(DispatchEventResult dispatchResult)
@@ -167,8 +171,10 @@ void RespondWithObserver::didDispatchEvent(DispatchEventResult dispatchResult)
         return;
     }
 
-    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->didHandleFetchEvent(m_eventID);
+    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->respondToFetchEvent(m_eventID);
     m_state = Done;
+    m_observer->decrementPendingActivity();
+    m_observer.clear();
 }
 
 void RespondWithObserver::respondWith(ScriptState* scriptState, ScriptPromise scriptPromise, ExceptionState& exceptionState)
@@ -179,6 +185,7 @@ void RespondWithObserver::respondWith(ScriptState* scriptState, ScriptPromise sc
     }
 
     m_state = Pending;
+    m_observer->incrementPendingActivity();
     scriptPromise.then(
         ThenFunction::createFunction(scriptState, this, ThenFunction::Fulfilled),
         ThenFunction::createFunction(scriptState, this, ThenFunction::Rejected));
@@ -193,8 +200,10 @@ void RespondWithObserver::responseWasRejected(WebServiceWorkerResponseError erro
     // to a network error.
     WebServiceWorkerResponse webResponse;
     webResponse.setError(error);
-    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->didHandleFetchEvent(m_eventID, webResponse);
+    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->respondToFetchEvent(m_eventID, webResponse);
     m_state = Done;
+    m_observer->decrementPendingActivity();
+    m_observer.clear();
 }
 
 void RespondWithObserver::responseWasFulfilled(const ScriptValue& value)
@@ -257,11 +266,13 @@ void RespondWithObserver::responseWasFulfilled(const ScriptValue& value)
             buffer->startLoading(FetchDataLoader::createLoaderAsStream(outStream), new NoopLoaderClient);
         }
     }
-    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->didHandleFetchEvent(m_eventID, webResponse);
+    ServiceWorkerGlobalScopeClient::from(getExecutionContext())->respondToFetchEvent(m_eventID, webResponse);
     m_state = Done;
+    m_observer->decrementPendingActivity();
+    m_observer.clear();
 }
 
-RespondWithObserver::RespondWithObserver(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext)
+RespondWithObserver::RespondWithObserver(ExecutionContext* context, int eventID, const KURL& requestURL, WebURLRequest::FetchRequestMode requestMode, WebURLRequest::FrameType frameType, WebURLRequest::RequestContext requestContext, WaitUntilObserver* observer)
     : ContextLifecycleObserver(context)
     , m_eventID(eventID)
     , m_requestURL(requestURL)
@@ -269,11 +280,13 @@ RespondWithObserver::RespondWithObserver(ExecutionContext* context, int eventID,
     , m_frameType(frameType)
     , m_requestContext(requestContext)
     , m_state(Initial)
+    , m_observer(observer)
 {
 }
 
 DEFINE_TRACE(RespondWithObserver)
 {
+    visitor->trace(m_observer);
     ContextLifecycleObserver::trace(visitor);
 }