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

net/quic/test_tools/quic_stream_sequencer_peer.cc

 // Copyright 2014 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.
 
 #include "net/quic/test_tools/quic_stream_sequencer_peer.h"
 
 #include "net/quic/quic_stream_sequencer.h"
 
 using std::map;
 using std::string;
 
 namespace net {
 namespace test {
 
 // static
-size_t QuicStreamSequencerPeer::GetNumBufferedFrames(
+size_t QuicStreamSequencerPeer::GetNumBufferedBytes(
     QuicStreamSequencer* sequencer) {
-  return sequencer->buffered_frames_.size();
+  return sequencer->buffered_frames_->BytesBuffered();
 }
 
 // static
 bool QuicStreamSequencerPeer::FrameOverlapsBufferedData(
-    QuicStreamSequencer* sequencer,
+    QuicFrameList* buffer,
     const QuicStreamFrame& frame) {
   list<QuicFrameList::FrameData>::iterator it =
-      sequencer->buffered_frames_.FindInsertionPoint(frame.offset,
-                                                     frame.data.length());
-  return sequencer->buffered_frames_.FrameOverlapsBufferedData(
-      frame.offset, frame.data.length(), it);
+      buffer->FindInsertionPoint(frame.offset, frame.data.length());
+  return buffer->FrameOverlapsBufferedData(frame.offset, frame.data.length(),
+                                           it);
 }
 
 // static
 QuicStreamOffset QuicStreamSequencerPeer::GetCloseOffset(
     QuicStreamSequencer* sequencer) {
   return sequencer->close_offset_;
 }
 
 }  // namespace test
 }  // namespace net