Rewrite scoped_ptr<T>(NULL) to use the default ctor in net/.

net/base/filter.cc

 // Copyright (c) 2011 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/base/filter.h"
 
 #include "base/files/file_path.h"
 #include "base/strings/string_util.h"
 #include "net/base/gzip_filter.h"
 #include "net/base/io_buffer.h"
@@ skipping 304 matching lines @@
                          FILTER_TYPE_GZIP_HELPING_SDCH);
   encoding_types->insert(encoding_types->begin(), FILTER_TYPE_SDCH_POSSIBLE);
   return;
 }
 
 Filter::Filter()
     : stream_buffer_(NULL),
       stream_buffer_size_(0),
       next_stream_data_(NULL),
       stream_data_len_(0),
-      next_filter_(NULL),
-      last_status_(FILTER_NEED_MORE_DATA) {
-}
+      last_status_(FILTER_NEED_MORE_DATA) {}
 
 Filter::FilterStatus Filter::CopyOut(char* dest_buffer, int* dest_len) {
   int out_len;
   int input_len = *dest_len;
   *dest_len = 0;
 
   if (0 == stream_data_len_)
     return Filter::FILTER_NEED_MORE_DATA;
 
   out_len = std::min(input_len, stream_data_len_);
@@ skipping 61 matching lines @@
 
 void Filter::PushDataIntoNextFilter() {
   IOBuffer* next_buffer = next_filter_->stream_buffer();
   int next_size = next_filter_->stream_buffer_size();
   last_status_ = ReadFilteredData(next_buffer->data(), &next_size);
   if (FILTER_ERROR != last_status_)
     next_filter_->FlushStreamBuffer(next_size);
 }
 
 }  // namespace net