ServiceWorker: Bypass resolving a promise when ExecutionContext is gone

Source/modules/serviceworkers/ServiceWorker.cpp

Index: Source/modules/serviceworkers/ServiceWorker.cpp
diff --git a/Source/modules/serviceworkers/ServiceWorker.cpp b/Source/modules/serviceworkers/ServiceWorker.cpp
index 2974a93ab3584ea5965086125359c4ee211fae8d..2bdf84df6a6dd01764ee808dacd7219658880aa7 100644
--- a/Source/modules/serviceworkers/ServiceWorker.cpp
+++ b/Source/modules/serviceworkers/ServiceWorker.cpp
@@ -156,6 +156,12 @@ PassRefPtrWillBeRawPtr<ServiceWorker> ServiceWorker::from(ExecutionContext* exec
 
 PassRefPtrWillBeRawPtr<ServiceWorker> ServiceWorker::from(ScriptPromiseResolver* resolver, WebType* worker)
 {
+    if (resolver->scriptState()->contextIsEmpty()) {

[haraken, 2014/07/17 07:53:36]

Shouldn't this check be if(!resolver->scriptState->executionContext()) ?

It's possible that a V8 context is not empty but the execution context is gone.
I guess what we want to check here is to check the existence of the execution
context.

[nhiroki, 2014/07/17 08:30:02]

ScriptState::executionContext() refers to V8::Context and it crashes if the v8
context is empty. Should we check an existence of the v8 context in
ScriptState::executionContext() ...?

+        if (worker && !worker->proxy())
+            delete worker;

[haraken, 2014/07/17 07:53:36]

I don't understand the memory management here either...

+        return nullptr;
+    }
+
     RefPtrWillBeRawPtr<ServiceWorker> serviceWorker = ServiceWorker::from(resolver->scriptState()->executionContext(), worker);
     ScriptState::Scope scope(resolver->scriptState());
     serviceWorker->waitOnPromise(resolver->promise());