[Fetch API] Request's JS wrapper should be kept alive in FetchEvent

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

 // Copyright 2016 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.
 
 #include "modules/serviceworkers/ForeignFetchEvent.h"
 
+#include "bindings/core/v8/ToV8.h"
+#include "bindings/core/v8/V8HiddenValue.h"
 #include "modules/fetch/Request.h"
 #include "modules/serviceworkers/ServiceWorkerGlobalScope.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 ForeignFetchEvent* ForeignFetchEvent::create()
 {
     return new ForeignFetchEvent();
 }
 
-ForeignFetchEvent* ForeignFetchEvent::create(const AtomicString& type, const ForeignFetchEventInit& initializer)
+ForeignFetchEvent* ForeignFetchEvent::create(ScriptState* scriptState, const AtomicString& type, const ForeignFetchEventInit& initializer)
 {
-    return new ForeignFetchEvent(type, initializer, nullptr);
+    return new ForeignFetchEvent(scriptState, type, initializer, nullptr);
 }
 
-ForeignFetchEvent* ForeignFetchEvent::create(const AtomicString& type, const ForeignFetchEventInit& initializer, ForeignFetchRespondWithObserver* observer)
+ForeignFetchEvent* ForeignFetchEvent::create(ScriptState* scriptState, const AtomicString& type, const ForeignFetchEventInit& initializer, ForeignFetchRespondWithObserver* observer)
 {
-    return new ForeignFetchEvent(type, initializer, observer);
+    return new ForeignFetchEvent(scriptState, type, initializer, observer);
 }
 
 Request* ForeignFetchEvent::request() const
 {
     return m_request;
 }
 
 String ForeignFetchEvent::origin() const
 {
     return m_origin;
 }
 
 void ForeignFetchEvent::respondWith(ScriptState* scriptState, ScriptPromise scriptPromise, ExceptionState& exceptionState)
 {
     stopImmediatePropagation();
     if (m_observer)
         m_observer->respondWith(scriptState, scriptPromise, exceptionState);
 }
 
 const AtomicString& ForeignFetchEvent::interfaceName() const
 {
     return EventNames::ForeignFetchEvent;
 }
 
 ForeignFetchEvent::ForeignFetchEvent()
 {
 }
 
-ForeignFetchEvent::ForeignFetchEvent(const AtomicString& type, const ForeignFetchEventInit& initializer, ForeignFetchRespondWithObserver* observer)
+ForeignFetchEvent::ForeignFetchEvent(ScriptState* scriptState, const AtomicString& type, const ForeignFetchEventInit& initializer, ForeignFetchRespondWithObserver* observer)
     : ExtendableEvent(type, initializer)
     , m_observer(observer)
 {
-    if (initializer.hasRequest())
-        m_request = initializer.request();
     if (initializer.hasOrigin())
         m_origin = initializer.origin();
+    if (initializer.hasRequest()) {
+        m_request = initializer.request();
+        ScriptState::Scope scope(scriptState);
+        m_request = initializer.request();
+        v8::Local<v8::Value> request = toV8(m_request, scriptState);
+        v8::Local<v8::Value> event = toV8(this, scriptState);
+        if (event.IsEmpty()) {
+            // |toV8| can return an empty handle when the worker is terminating.
+            // We don't want the renderer to crash in such cases.
+            // TODO(yhirano): Replace this branch with an assertion.
+            return;
+        }
+        DCHECK(event->IsObject());
+        // Sets an hidden value in order to teach V8 the dependency from
+        // the event to the request.
+        V8HiddenValue::setHiddenValue(scriptState, event.As<v8::Object>(), V8HiddenValue::requestInFetchEvent(scriptState->isolate()), request);
+        // As written above, we don't check the return value.
+        // TODO(yhirano): Add an assertion.

[falken, 2016/06/02 08:36:32]

Similar comments here as in FetchEvent (too bad this code is duplicated, is it
worth trying to refactor it out?)

[yhirano, 2016/06/02 10:10:11]

I think it's OK to be duplicated because I will update the implementation later.
With proper mechanisms this code will be gone (See PS4 or PS5).

+    }
 }
 
 DEFINE_TRACE(ForeignFetchEvent)
 {
     visitor->trace(m_observer);
     visitor->trace(m_request);
     ExtendableEvent::trace(visitor);
 }
 
 } // namespace blink