Move quic_bug_tracker to quic/platform. No functional change expected.

net/quic/core/quic_stream_sequencer_buffer.cc

 // Copyright (c) 2015 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/core/quic_stream_sequencer_buffer.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
-#include "net/quic/core/quic_bug_tracker.h"
 #include "net/quic/core/quic_flags.h"
+#include "net/quic/platform/api/quic_bug_tracker.h"
 #include "net/quic/platform/api/quic_str_cat.h"
 
 using std::string;
 
 namespace net {
 namespace {
 
 // Upper limit of how many gaps allowed in buffer, which ensures a reasonable
 // number of iterations needed to find the right gap to fill when a frame
 // arrives.
@@ skipping 570 matching lines @@
     QuicStreamOffset current_frame_end_offset =
         it.second.length + current_frame_begin_offset;
     current_frames_string.append(QuicStrCat(
         "[", current_frame_begin_offset, ", ", current_frame_end_offset,
         ") receiving time ", it.second.timestamp.ToDebuggingValue()));
   }
   return current_frames_string;
 }
 
 }  //  namespace net