[Presentation API] PresentationRequest::getAvailability() should return the same promise

third_party/WebKit/Source/modules/presentation/PresentationRequest.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 "modules/presentation/PresentationRequest.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
@@ skipping 171 matching lines @@
     return rejectWithSandBoxException(scriptState);
 
   WebPresentationClient* client = presentationClient(getExecutionContext());
   if (!client)
     return ScriptPromise::rejectWithDOMException(
         scriptState,
         DOMException::create(
             InvalidStateError,
             "The PresentationRequest is no longer associated to a frame."));
 
-  ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
-  client->getAvailability(
-      m_url,
-      WTF::makeUnique<PresentationAvailabilityCallbacks>(resolver, m_url));
-  return resolver->promise();
+  if (!m_availabilityProperty) {
+    m_availabilityProperty = new PresentationAvailabilityProperty(
+        scriptState->getExecutionContext(), this,
+        PresentationAvailabilityProperty::Ready);
+
+    client->getAvailability(m_url,
+                            WTF::makeUnique<PresentationAvailabilityCallbacks>(
+                                m_availabilityProperty, m_url));
+  }
+  return m_availabilityProperty->promise(scriptState->world());
 }
 
 const KURL& PresentationRequest::url() const {
   return m_url;
 }
 
 DEFINE_TRACE(PresentationRequest) {
+  visitor->trace(m_availabilityProperty);
   EventTargetWithInlineData::trace(visitor);
   SuspendableObject::trace(visitor);
 }
 
 PresentationRequest::PresentationRequest(ExecutionContext* executionContext,
                                          const KURL& url)
     : SuspendableObject(executionContext), m_url(url) {}
 
 }  // namespace blink