[SPDY] Incorporate latest framing changes from HTTP2 into SPDY 4 as SPDY 4a2.

net/spdy/spdy_frame_builder.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_FRAME_BUILDER_H_
 #define NET_SPDY_SPDY_FRAME_BUILDER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 32 matching lines @@
   // Returns NULL on failure.
   char* GetWritableBuffer(size_t length);
 
   // Seeks forward by the given number of bytes. Useful in conjunction with
   // GetWriteableBuffer() above.
   bool Seek(size_t length);
 
   // Populates this frame with a SPDY control frame header using
   // version-specific information from the |framer| and length information from
   // capacity_. The given type must be a control frame type.
+  // Used only for SPDY versions <4.
   bool WriteControlFrameHeader(const SpdyFramer& framer,
                                SpdyFrameType type,
                                uint8 flags);
 
   // Populates this frame with a SPDY data frame header using version-specific
   // information from the |framer| and length information from capacity_.
   bool WriteDataFrameHeader(const SpdyFramer& framer,
                             SpdyStreamId stream_id,
                             SpdyDataFlags flags);
 
+  // Populates this frame with a SPDY4/HTTP2 frame prefix using
+  // version-specific information from the |framer| and length information from
+  // capacity_. The given type must be a control frame type.
+  // Used only for SPDY versions >=4.
+  bool WriteFramePrefix(const SpdyFramer& framer,
+                        SpdyFrameType type,
+                        uint8 flags,
+                        SpdyStreamId stream_id);
+
   // Takes the buffer from the SpdyFrameBuilder.
   SpdyFrame* take() {
     SpdyFrame* rv = new SpdyFrame(buffer_.release(), length_, true);
     capacity_ = 0;
     length_ = 0;
     return rv;
   }
 
   // Methods for adding to the payload.  These values are appended to the end
   // of the SpdyFrameBuilder payload. Note - binary integers are converted from
@@ skipping 37 matching lines @@
   bool CanWrite(size_t length) const;
 
   scoped_ptr<char[]> buffer_;
   size_t capacity_;  // Allocation size of payload, set by constructor.
   size_t length_;    // Current length of the buffer.
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_FRAME_BUILDER_H_