Fix failure of reading zero-byte files on Drive via StreamReader.

Fix failure of reading zero-byte files on Drive via StreamReader.

HttpByteRange by its nature represents ranges in inclusive format.
We should avoid using it during computation that might involve
empty ranges. In the old code, [0-*].ComputeBounds(0) was failing.

BUG=329328
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=242063

[hashimoto, 2013-12-19 08:53:40]

https://codereview.chromium.org/93883006/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/drive_file_stream_reader.cc (right):

https://codereview.chromium.org/93883006/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.cc:357: // Convert it to
half-exclusive range with missing bounds filled.
Is it OK to ignore suffix byte range?

[kinaba, 2013-12-20 03:57:55]

PTAL once again.

I thought a short while about "upstreaming" the wrapper into net::HttpByteRange
itself,
but it seems that the current behavior of ComputeBounds is exactly what
is needed for all the other callers. (The behavior matches how, e.g., Apache
HTTP server responds to the range requests.)

https://codereview.chromium.org/93883006/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/drive_file_stream_reader.cc (right):

https://codereview.chromium.org/93883006/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/drive_file_stream_reader.cc:357: // Convert it to
half-exclusive range with missing bounds filled.
On 2013/12/19 08:53:40, hashimoto wrote:
> Is it OK to ignore suffix byte range?

Good catch. Recovered the support for suffix range by
delegating the impl to HttpByteRange except for the corner case.

[hashimoto, 2013-12-20 04:09:46]

lgtm

[commit-bot: I haz the power, 2013-12-20 07:19:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kinaba@chromium.org/93883006/50001

[commit-bot: I haz the power, 2013-12-20 11:07:15]

Change committed as 242063