Add a pre-finalizer to PromiseRejectionEvent

third_party/WebKit/Source/core/events/PromiseRejectionEvent.cpp

 // Copyright 2015 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 "core/events/PromiseRejectionEvent.h"
 
 #include "bindings/core/v8/DOMWrapperWorld.h"
 
 namespace blink {
 
 PromiseRejectionEvent::PromiseRejectionEvent()
 {
 }
 
 PromiseRejectionEvent::PromiseRejectionEvent(ScriptState* state, const AtomicString& type, const PromiseRejectionEventInit& initializer)
     : Event(type, initializer)
     , m_scriptState(state)
 {
+    ThreadState::current()->registerPreFinalizer(this);
     ASSERT(initializer.hasPromise());
     m_promise.set(initializer.promise().isolate(), initializer.promise().v8Value());
     m_promise.setPhantom();
     if (initializer.hasReason()) {
         m_reason.set(initializer.reason().isolate(), initializer.reason().v8Value());
         m_reason.setPhantom();
     }
 }
 
 PromiseRejectionEvent::~PromiseRejectionEvent()
 {
 }
 
+void PromiseRejectionEvent::dispose()
+{
+    // Clear ScopedPersistents so that V8 doesn't call phantom callbacks
+    // (and touch the ScopedPersistents) after Oilpan starts lazy sweeping.
+    m_promise.clear();

[sof, 2016/07/29 16:34:09]

Please clear m_scriptState also.

+    m_reason.clear();
+}
+
 ScriptPromise PromiseRejectionEvent::promise(ScriptState* state) const
 {
     // Return null when the promise is accessed by a different world than the world that created the promise.
     if (!m_scriptState || !m_scriptState->contextIsValid() || m_scriptState->world().worldId() != state->world().worldId())
         return ScriptPromise();
     return ScriptPromise(m_scriptState.get(), m_promise.newLocal(m_scriptState->isolate()));
 }
 
 ScriptValue PromiseRejectionEvent::reason(ScriptState* state) const
 {
@@ skipping 30 matching lines @@
     Event::trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(PromiseRejectionEvent)
 {
     visitor->traceWrappers(&m_promise);
     visitor->traceWrappers(&m_reason);
 }
 
 } // namespace blink