Improve documentation on Filter and fix pipeline overwrite.

net/filter/filter.h

 // 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.
 //
 // Filter performs filtering on data streams. Sample usage:
 //
 //   IStream* pre_filter_source;
 //   ...
 //   Filter* filter = Filter::Factory(filter_type, size);
 //   int pre_filter_data_len = filter->stream_buffer_size();
 //   pre_filter_source->read(filter->stream_buffer(), pre_filter_data_len);
 //
 //   filter->FlushStreamBuffer(pre_filter_data_len);
 //
 //   char post_filter_buf[kBufferSize];
 //   int post_filter_data_len = kBufferSize;
 //   filter->ReadFilteredData(post_filter_buf, &post_filter_data_len);
 //
 // To filter a data stream, the caller first gets filter's stream_buffer_
 // through its accessor and fills in stream_buffer_ with pre-filter data, next
 // calls FlushStreamBuffer to notify Filter, then calls ReadFilteredData
 // repeatedly to get all the filtered data. After all data have been fitlered

[Bence, 2014/10/29 20:00:24]

s/fitlered/filtered/ once you are here.  Thanks.

[Randy Smith (Not in Mondays), 2014/10/30 18:35:42]

Done.

-// and read out, the caller may fill in stream_buffer_ again. This
+// and read out, the caller may fill in stream_buffer_ again.  This
 // WriteBuffer-Flush-Read cycle is repeated until reaching the end of data
 // stream.
 //
+// A return of FILTER_OK from ReadData() means that more data is
+// available to a future ReadData() call and data may not be written
+// into stream_buffer().  A return of FILTER_NEED_MORE_DATA from ReadData()
+// means that the buffer at stream_buffer() is available for writing.
+//
 // The lifetime of a Filter instance is completely controlled by its caller.
 
 #ifndef NET_FILTER_FILTER_H__
 #define NET_FILTER_FILTER_H__
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
@@ skipping 238 matching lines @@
   // Remember what status or local filter last returned so we can better handle
   // chained filters.
   FilterStatus last_status_;
 
   DISALLOW_COPY_AND_ASSIGN(Filter);
 };
 
 }  // namespace net
 
 #endif  // NET_FILTER_FILTER_H__