Make peeking before the head of OffsetByteQueue a hard error.

Make peeking before the head of OffsetByteQueue a hard error.

BUG=
TEST=OffsetByteQueueTest


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=149293

[strobe_, 2012-07-28 06:05:32]

Hi Aaron, a small CL to make one kind of bug stand out more, which may have made
the condition in http://codereview.chromium.org/10826056/ more obvious. 

This adds a death test, which seems unused in media/, and triggers a gunit
warning. I'm fine simply removing the test case that triggers the DCHECK if that
makes more sense.

[acolwell GONE FROM CHROMIUM, 2012-07-30 20:49:04]

http://codereview.chromium.org/10823069/diff/1/media/mp4/offset_byte_queue.cc
File media/mp4/offset_byte_queue.cc (right):

http://codereview.chromium.org/10823069/diff/1/media/mp4/offset_byte_queue.cc...
media/mp4/offset_byte_queue.cc:40: DCHECK(offset >= head());
Is this a result of a coding error, or can unexpected or corrupt files trigger
this? If it is the former then I'm fine with the DCHECK. If it is the later then
I'd prefer the original code since this situation should allow us to signal an
error w/o crashing.

[strobe_, 2012-07-31 18:34:38]

https://chromiumcodereview.appspot.com/10823069/diff/1/media/mp4/offset_byte_...
File media/mp4/offset_byte_queue.cc (right):

https://chromiumcodereview.appspot.com/10823069/diff/1/media/mp4/offset_byte_...
media/mp4/offset_byte_queue.cc:40: DCHECK(offset >= head());
On 2012/07/30 20:49:04, acolwell wrote:
> Is this a result of a coding error, or can unexpected or corrupt files trigger
> this? If it is the former then I'm fine with the DCHECK. If it is the later
then
> I'd prefer the original code since this situation should allow us to signal an
> error w/o crashing.

As of now, it can only be the result of a programming error. (Formerly, it could
have been the result of a corrupt file, but recent changes eliminate that.)

[acolwell GONE FROM CHROMIUM, 2012-07-31 19:27:44]

LGTM

https://chromiumcodereview.appspot.com/10823069/diff/1/media/mp4/offset_byte_...
File media/mp4/offset_byte_queue_unittest.cc (right):

https://chromiumcodereview.appspot.com/10823069/diff/1/media/mp4/offset_byte_...
media/mp4/offset_byte_queue_unittest.cc:60: ASSERT_DEATH(queue_->PeekAt(128,
&buf, &size), "offset >= head");
Remove this since you said this situation only happens as a result of a coding
error. No need to test that the DCHECK is there.

[commit-bot: I haz the power, 2012-07-31 20:45:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/strobe@google.com/10823069/7001

[commit-bot: I haz the power, 2012-07-31 22:18:04]

Change committed as 149293