Add FileReaderInterface. Move StringFileWriter to StringFile and

Add FileReaderInterface. Move StringFileWriter to StringFile and
implement the new interface.

The upcoming minidump reader will get minidump data from a
FileReaderInterface. For ease of testing, a string-based implementation
is provided. There wasn’t a good reason to have a separate
StringFileReader and StringFileWriter, so I combined them into a single
StringFile.

TEST=util_test StringFile.*
R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/583233cf78e9767f806b9897b1bc9881dccbc815

[Mark Mentovai, 2015-02-18 17:58:07]

The changes in minidump are almost all mechanical, made by sed.

It’s unfortunate that git didn’t detect string_file_test.cc as a copy from
string_file_writer_test.cc. Would you like a separate change to move
string_file_writer* to string_file* first to ease the review?

[Mark Mentovai, 2015-02-18 17:58:18]

mark@chromium.org changed reviewers:
+ rsesek@chromium.org

[Mark Mentovai, 2015-02-18 17:58:19]

The changes in minidump are almost all mechanical, made by sed.

It’s unfortunate that git didn’t detect string_file_test.cc as a copy from
string_file_writer_test.cc. Would you like a separate change to move
string_file_writer* to string_file* first to ease the review?

[Robert Sesek, 2015-02-18 18:44:28]

https://codereview.chromium.org/936153002/diff/1/util/file/file_reader.cc
File util/file/file_reader.cc (right):

https://codereview.chromium.org/936153002/diff/1/util/file/file_reader.cc#new...
util/file/file_reader.cc:31: // TODO(mark): Read no more than SSIZE_MAX bytes in
a single call.
In LoggingReadFile, you just use a checked_cast for this.

https://codereview.chromium.org/936153002/diff/1/util/file/file_reader.h
File util/file/file_reader.h (right):

https://codereview.chromium.org/936153002/diff/1/util/file/file_reader.h#newc...
util/file/file_reader.h:1: // Copyright 2014 The Crashpad Authors. All rights
reserved.
2015

https://codereview.chromium.org/936153002/diff/1/util/file/file_reader.h#newc...
util/file/file_reader.h:29: // TODO(mark): Templatize and share more with
FileWriterInterface?
Wouldn't this just be a FileSeekerInterface ?

[Mark Mentovai, 2015-02-18 19:07:20]

All feedback addressed. Updated.

[Robert Sesek, 2015-02-18 19:13:19]

LGTM

https://codereview.chromium.org/936153002/diff/20001/util/file/file_seeker.h
File util/file/file_seeker.h (right):

https://codereview.chromium.org/936153002/diff/20001/util/file/file_seeker.h#...
util/file/file_seeker.h:18: #include <sys/types.h>
Unused?

[Mark Mentovai, 2015-02-18 19:15:01]

New patchsets have been uploaded after l-g-t-m from rsesek@chromium.org

[Mark Mentovai, 2015-02-18 19:15:42]

Committed patchset #3 (id:40001) manually as
583233cf78e9767f806b9897b1bc9881dccbc815 (presubmit successful).