[SPDY] Replace SpdyIOBuffer with new SpdyBuffer class

net/spdy/spdy_buffer_producer.h

+// Copyright (c) 2013 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 NET_SPDY_SPDY_BUFFER_PRODUCER_H_
+#define NET_SPDY_SPDY_BUFFER_PRODUCER_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/base/net_export.h"
+
+namespace net {
+
+class SpdyBuffer;
+
+// An object which provides a SpdyBuffer for writing. We pass these
+// around instead of SpdyBuffers since some buffers have to be
+// generated "just in time".
+class NET_EXPORT_PRIVATE SpdyBufferProducer {
+ public:
+  SpdyBufferProducer();
+
+  // Produces the buffer to be written. Will be called at most once.
+  virtual scoped_ptr<SpdyBuffer> ProduceBuffer() = 0;
+
+  virtual ~SpdyBufferProducer();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SpdyBufferProducer);
+};
+
+// A simple wrapper around a single SpdyBuffer.
+class NET_EXPORT_PRIVATE SimpleBufferProducer : public SpdyBufferProducer {
+ public:
+  explicit SimpleBufferProducer(scoped_ptr<SpdyBuffer> buffer);
+
+  virtual ~SimpleBufferProducer();
+
+  virtual scoped_ptr<SpdyBuffer> ProduceBuffer() OVERRIDE;
+
+ private:
+  scoped_ptr<SpdyBuffer> buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(SimpleBufferProducer);
+};
+
+}  // namespace net
+
+#endif  // NET_SPDY_SPDY_BUFFER_PRODUCER_H_