[Courgette] Refactor BSDiff namespaces and bsdiff::search() interface.

courgette/third_party/bsdiff/bsdiff_apply.cc

 // Copyright 2003, 2004 Colin Percival
 // All rights reserved
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted providing that the following conditions
 // are met:
 // 1. Redistributions of source code must retain the above copyright
 //    notice, this list of conditions and the following disclaimer.
 // 2. Redistributions in binary form must reproduce the above copyright
 //    notice, this list of conditions and the following disclaimer in the
@@ skipping 26 matching lines @@
 
 #include "courgette/third_party/bsdiff/bsdiff.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/files/memory_mapped_file.h"
 #include "courgette/crc.h"
 #include "courgette/streams.h"
 
-namespace courgette {
+namespace {
+
+using courgette::CalculateCrc;
+using courgette::SinkStream;
+using courgette::SinkStreamSet;
+using courgette::SourceStream;
+using courgette::SourceStreamSet;
+
+}  // namespace
+
+namespace bsdiff {
 
 BSDiffStatus MBS_ReadHeader(SourceStream* stream, MBSPatchHeader* header) {
   if (!stream->Read(header->tag, sizeof(header->tag)))
     return READ_ERROR;
   if (!stream->ReadVarint32(&header->slen))
     return READ_ERROR;
   if (!stream->ReadVarint32(&header->scrc32))
     return READ_ERROR;
   if (!stream->ReadVarint32(&header->dlen))
     return READ_ERROR;
@@ skipping 150 matching lines @@
 
   // Write the stream to disk.
   int written = base::WriteFile(
       new_file_path, reinterpret_cast<const char*>(new_sink_stream.Buffer()),
       static_cast<int>(new_sink_stream.Length()));
   if (written != static_cast<int>(new_sink_stream.Length()))
     return WRITE_ERROR;
   return OK;
 }
 
-}  // namespace
+}  // namespace bsdiff