AU: delta compress the kernel partition

src/platform/update_engine/extent_writer_unittest.cc

 // Copyright (c) 2009 The Chromium OS 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 <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <algorithm>
 #include <string>
 #include <vector>
@@ skipping 219 matching lines @@
   size_t bytes_written = 0;
   while (bytes_written < (block_count * kBlockSize)) {
     size_t bytes_to_write = min(block_count * kBlockSize - bytes_written,
                                 data.size());
     EXPECT_TRUE(direct_writer.Write(&data[0], bytes_to_write));
     bytes_written += bytes_to_write;
   }
   EXPECT_TRUE(direct_writer.End());
   
   // check file size, then data inside
-  ASSERT_EQ(2 * kBlockSize, FileSize(path()));
+  ASSERT_EQ(2 * kBlockSize, utils::FileSize(path()));
   
   vector<char> resultant_data;
   EXPECT_TRUE(utils::ReadFile(path(), &resultant_data));
   
   // Create expected data
   vector<char> expected_data(on_disk_count * kBlockSize);
   vector<char> big(block_count * kBlockSize);
   for (vector<char>::size_type i = 0; i < big.size(); i++) {
     big[i] = data[i % data.size()];
   }
   memcpy(&expected_data[kBlockSize], &big[0], kBlockSize);
   memcpy(&expected_data[0], &big[3 * kBlockSize], kBlockSize);
   ExpectVectorsEq(expected_data, resultant_data);
 }
 
 }  // namespace chromeos_update_engine