Add a SpdyFramer extension API implementation.

net/spdy/spdy_framer.h

 // Copyright (c) 2012 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_FRAMER_H_
 #define NET_SPDY_SPDY_FRAMER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 195 matching lines @@
                           int weight,
                           bool exclusive) {}
 
   // Called when a frame type we don't recognize is received.
   // Return true if this appears to be a valid extension frame, false otherwise.
   // We distinguish between extension frames and nonsense by checking
   // whether the stream id is valid.
   virtual bool OnUnknownFrame(SpdyStreamId stream_id, uint8_t frame_type) = 0;
 };
 
+class SpdyFrameSequence {
+ public:
+  virtual ~SpdyFrameSequence() {}
+
+  // Serializes the next frame in the sequence to |output|. Returns the number
+  // of bytes written to |output|.
+  virtual size_t NextFrame(ZeroCopyOutputBuffer* output) = 0;
+
+  // Returns true iff there is at least one more frame in the sequence.
+  virtual bool HasNextFrame() const = 0;
+};
+
 class ExtensionVisitorInterface {
  public:
   virtual ~ExtensionVisitorInterface() {}
 
   // Called when non-standard SETTINGS are received.
   virtual void OnSetting(uint16_t id, uint32_t value) = 0;
 
   // Called when non-standard frames are received.
   virtual bool OnFrameHeader(SpdyStreamId stream_id,
                              size_t length,
@@ skipping 652 matching lines @@
   // rather than reading all available input.
   bool process_single_input_frame_ = false;
 
   // Latched value of FLAGS_chromium_http2_flag_remove_rewritelength.
   bool skip_rewritelength_ = false;
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_FRAMER_H_