[Fetch API] Remove DrainingBuffer.

Source/core/streams/ReadableByteStreamReader.h

 // 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.
 
 #ifndef ReadableByteStreamReader_h
 #define ReadableByteStreamReader_h
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/CoreExport.h"
 #include "core/streams/ReadableStreamReader.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class ExceptionState;
 class ScriptState;
 
 class CORE_EXPORT ReadableByteStreamReader final : public GarbageCollectedFinalized<ReadableByteStreamReader>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     explicit ReadableByteStreamReader(ReadableStreamReader* reader) : m_reader(reader) { }
 
     ScriptPromise closed(ScriptState* scriptState) { return m_reader->closed(scriptState); }
     ScriptPromise read(ScriptState* scriptState) { return m_reader->read(scriptState); }
     ScriptPromise cancel(ScriptState* scriptState) { return m_reader->cancel(scriptState); }
     ScriptPromise cancel(ScriptState* scriptState, ScriptValue reason) { return m_reader->cancel(scriptState, reason); }
     void releaseLock(ExceptionState& es) { return m_reader->releaseLock(es); }
+    void releaseLock() { return m_reader->releaseLock(); }
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
         visitor->trace(m_reader);
     }
 
 private:
     Member<ReadableStreamReader> m_reader;
 };
 
 } // namespace blink
 
 #endif // ReadableByteStreamReader_h