Implement BodyStreamBuffer::create() from WebDataConsumerHandle

Source/modules/fetch/BodyStreamBuffer.h

 // Copyright 2014 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.
 
 #ifndef BodyStreamBuffer_h
 #define BodyStreamBuffer_h
 
 #include "core/dom/DOMException.h"
 #include "modules/ModulesExport.h"
 #include "platform/blob/BlobData.h"
 #include "platform/heap/Heap.h"
+#include "public/platform/WebDataConsumerHandle.h"
 #include "wtf/Deque.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class DOMArrayBuffer;
 
 class MODULES_EXPORT BodyStreamBuffer final : public GarbageCollectedFinalized<BodyStreamBuffer> {
 public:
@@ skipping 42 matching lines @@
     // This function registers an observer so it fails and returns false when an
     // observer was already registered.
     bool startTee(BodyStreamBuffer* out1, BodyStreamBuffer* out2);
 
     // When an observer was registered this function fails and returns false.
     bool registerObserver(Observer*);
     void unregisterObserver();
     bool isObserverRegistered() const { return m_observer.get(); }
     DECLARE_TRACE();
 
+    // Creates a BodyStreamBuffer from |handle| as the source.
+    // On failure, BodyStreamBuffer::error() is called with a NetworkError
+    // with |failureMessage|.
+    static BodyStreamBuffer* create(PassOwnPtr<WebDataConsumerHandle> /* handle */, const String& failureMessage);
+
 private:
     Deque<RefPtr<DOMArrayBuffer>> m_queue;
     bool m_isClosed;
     Member<DOMException> m_exception;
     Member<Observer> m_observer;
     Member<Canceller> m_canceller;
 };
 
 } // namespace blink
 
 #endif // BodyStreamBuffer_h