Add truncation to StreamCopyOrMoveImpl and test case.

content/browser/fileapi/file_system_operation_impl_unittest.cc

 // Copyright 2013 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 "webkit/browser/fileapi/file_system_operation_impl.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
@@ skipping 1269 matching lines @@
       base::Bind(&AssertFileErrorEq, FROM_HERE, base::File::FILE_OK));
   base::RunLoop().RunUntilIdle();
 
   expected_usage += grandchild_file_size + grandchild_path_cost;
   usage = GetUsage();
   EXPECT_EQ(2 * child_file_size + 3 * grandchild_file_size,
             GetDataSizeOnDisk());
   EXPECT_EQ(expected_usage, usage);
 }
 
+TEST_F(FileSystemOperationImplTest,
+       TestCopySuccessSrcFileWithDifferentFileSize) {
+  FileSystemURL src_file(CreateFile("src"));
+  FileSystemURL dest_file(CreateFile("dest"));
+  operation_runner()->Truncate(dest_file, 6, RecordStatusCallback());
+  base::RunLoop().RunUntilIdle();
+
+  operation_runner()->Copy(src_file,
+                           dest_file,
+                           FileSystemOperation::OPTION_NONE,
+                           FileSystemOperationRunner::CopyProgressCallback(),
+                           RecordStatusCallback());
+  base::RunLoop().RunUntilIdle();

[tzik, 2014/09/03 02:07:43]

This doesn't run the modified part of the code untile we enable the stream copy
for sandboxed filesystem...

Can we use Run() instead of RunUntilIdle()?

[iseki, 2014/09/03 03:28:21]

Done.

+  EXPECT_EQ(0, GetFileSize("dest"));
+  EXPECT_EQ(base::File::FILE_OK, status());
+}
+
 }  // namespace content