Have ScriptPromiseResolver on the Oilpan heap always.

Source/core/streams/ReadableStreamImpl.h

Index: Source/core/streams/ReadableStreamImpl.h
diff --git a/Source/core/streams/ReadableStreamImpl.h b/Source/core/streams/ReadableStreamImpl.h
index 719fe8e040a940fe2c8cb9456434f1bfc9b3cee0..27ee8ce5de6082de5f5ac03a844e1ce77a46e360 100644
--- a/Source/core/streams/ReadableStreamImpl.h
+++ b/Source/core/streams/ReadableStreamImpl.h
@@ -118,18 +118,12 @@ public:
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
         visitor->trace(m_strategy);
-#if ENABLE(OILPAN)
         visitor->trace(m_pendingReads);
-#endif
         ReadableStream::trace(visitor);
     }
 
 private:
-#if ENABLE(OILPAN)
     using PendingReads = HeapDeque<Member<ScriptPromiseResolver>>;
-#else
-    using PendingReads = Deque<RefPtr<ScriptPromiseResolver>>;
-#endif
 
     // ReadableStream methods
     bool isQueueEmpty() const override { return m_queue.isEmpty(); }
@@ -142,8 +136,11 @@ private:
     void resolveAllPendingReadsAsDone() override
     {
         for (auto& resolver : m_pendingReads) {
-            ScriptState::Scope scope(resolver->scriptState());
-            resolver->resolve(v8IteratorResultDone(resolver->scriptState()));
+            ScriptState* scriptState = resolver->scriptState();
+            if (!scriptState->contextIsValid())
+                continue;
+            ScriptState::Scope scope(scriptState);
+            resolver->resolve(v8IteratorResultDone(scriptState));
         }
         m_pendingReads.clear();
     }
@@ -180,8 +177,10 @@ bool ReadableStreamImpl<ChunkTypeTraits>::enqueue(typename ChunkTypeTraits::Pass
         return enqueuePostAction();
     }
 
-    RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = m_pendingReads.takeFirst();
+    ScriptPromiseResolver* resolver = m_pendingReads.takeFirst();
     ScriptState* scriptState = resolver->scriptState();
+    if (!scriptState->contextIsValid())
+        return false;
     ScriptState::Scope scope(scriptState);
     resolver->resolve(v8IteratorResult(scriptState, chunk));
     return enqueuePostAction();