Add a SpdyFramer extension API implementation.

net/spdy/spdy_frame_builder.cc

Index: net/spdy/spdy_frame_builder.cc
diff --git a/net/spdy/spdy_frame_builder.cc b/net/spdy/spdy_frame_builder.cc
index 172f9d2ab6ce7825a0ec3d212f35ec4f0e9a5cc6..fcbd52f27114e3bf95e3a9396ae4e31ed6d94911 100644
--- a/net/spdy/spdy_frame_builder.cc
+++ b/net/spdy/spdy_frame_builder.cc
@@ -131,6 +131,14 @@ bool SpdyFrameBuilder::BeginNewFrame(const SpdyFramer& framer,
                                      size_t length) {
   uint8_t raw_frame_type = SerializeFrameType(type);
   DCHECK(IsDefinedFrameType(raw_frame_type));
+  return BeginNewFrame(framer, raw_frame_type, flags, stream_id, length);
+}
+
+bool SpdyFrameBuilder::BeginNewFrame(const SpdyFramer& framer,
+                                     uint8_t raw_frame_type,
+                                     uint8_t flags,
+                                     SpdyStreamId stream_id,
+                                     size_t length) {
   DCHECK_EQ(0u, stream_id & ~kStreamIdMask);
   bool success = true;
   SPDY_BUG_IF(framer.GetFrameMaximumSize() < length_)