Add an utility interface ReaderProxy and its implementation for local file.

Add an utility interface ReaderProxy and its implementation for local file.

This introduces a new utility interface ReaderProxy, which will be used to
implement DriveFileStreamReader, and its implementation for local file, named
LocalReaderProxy.

BUG=127129
TEST=Ran unit_tests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=194787

[hidehiko, 2013-04-16 07:54:34]

Thank you for your review in advance,
- hidehiko

[hashimoto, 2013-04-16 08:38:29]

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/drive_file_stream_reader.h (right):

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.h:27: // Conceptually
this is a part of implementation details for
nit: Is this sentence needed? The name of the namespace "internal" seems to be
telling everything.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.h:39: virtual void
OnGetContent(scoped_ptr<std::string> data) = 0;
Does this method need to be in this interface?
Only NetworkReaderProxy needs this.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.h:42: virtual void
OnError(DriveFileError error) = 0;
ditto.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc (right):

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc:39:
net::CompletionCallback callback =
How about using net::TestCompletionCallback?

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc:56: //
Prepare the buffer, which size is smaller than the whole data size.
nit: s/which/whose/?

[hidehiko, 2013-04-16 08:57:11]

Thank you for your review. Could you take another look?

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/drive_file_stream_reader.h (right):

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.h:27: // Conceptually
this is a part of implementation details for
On 2013/04/16 08:38:29, hashimoto wrote:
> nit: Is this sentence needed? The name of the namespace "internal" seems to be
> telling everything.

Ok. Removed.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.h:39: virtual void
OnGetContent(scoped_ptr<std::string> data) = 0;
On 2013/04/16 08:38:29, hashimoto wrote:
> Does this method need to be in this interface?
> Only NetworkReaderProxy needs this.

Yes, this needs to be a part of this interface, otherwise we'd need static_casts
inside DriveFileStreamReader implementation.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.h:42: virtual void
OnError(DriveFileError error) = 0;
On 2013/04/16 08:38:29, hashimoto wrote:
> ditto.

Acknowledged.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc (right):

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc:39:
net::CompletionCallback callback =
On 2013/04/16 08:38:29, hashimoto wrote:
> How about using net::TestCompletionCallback?

Good to know. Done.

https://codereview.chromium.org/14237004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc:56: //
Prepare the buffer, which size is smaller than the whole data size.
On 2013/04/16 08:38:29, hashimoto wrote:
> nit: s/which/whose/?

Oops. Done.

[hashimoto, 2013-04-16 09:00:44]

lgtm

[kinaba, 2013-04-17 00:50:33]

lgtm

[commit-bot: I haz the power, 2013-04-18 01:06:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hidehiko@chromium.org/14237004/19001

[commit-bot: I haz the power, 2013-04-18 05:42:35]

Change committed as 194787