Introduces QuicStreamSequencerBufferInterface with one implementation. Refactor, no behavior change.

net/quic/test_tools/quic_stream_sequencer_peer.h

Index: net/quic/test_tools/quic_stream_sequencer_peer.h
diff --git a/net/quic/test_tools/quic_stream_sequencer_peer.h b/net/quic/test_tools/quic_stream_sequencer_peer.h
index 22e3a9908b7b3ef5d5552b030d8640a07862ac72..e8421c16d6ae046695a7c9180c46a3fd04519702 100644
--- a/net/quic/test_tools/quic_stream_sequencer_peer.h
+++ b/net/quic/test_tools/quic_stream_sequencer_peer.h
@@ -6,6 +6,7 @@
 #define NET_QUIC_TEST_TOOLS_QUIC_STREAM_SEQUENCER_PEER_H_
 
 #include "base/basictypes.h"
+#include "net/quic/quic_frame_list.h"
 #include "net/quic/quic_protocol.h"
 
 namespace net {
@@ -16,9 +17,9 @@ namespace test {
 
 class QuicStreamSequencerPeer {
  public:
-  static size_t GetNumBufferedFrames(QuicStreamSequencer* sequencer);
+  static size_t GetNumBufferedBytes(QuicStreamSequencer* sequencer);
 
-  static bool FrameOverlapsBufferedData(QuicStreamSequencer* sequencer,
+  static bool FrameOverlapsBufferedData(QuicFrameList* buffer,
                                         const QuicStreamFrame& frame);
 
   static QuicStreamOffset GetCloseOffset(QuicStreamSequencer* sequencer);