Fix canPlayType() support for non-RFC compliant mp3 mimetype.

Fix canPlayType() support for non-RFC compliant mp3 mimetype.

The 'audio/mpeg; codecs="mp3"' mimetype is not RFC 3003 compliant, but a
bunch of sites apparently use it. This change restores the behavior that
was in M35 and earlier and returns "probably" for this mimetype.

The changes are intentionally kept small so they can be easily be merged
to the M36 & M37 branches.

BUG=393720, 386073
TEST=MediaCanPlayTypeTest.CodecSupportTest_mp3

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283929

[Ryan Sleevi, 2014-07-17 18:38:08]

LGTM with two nits.

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc
File net/base/mime_util.cc (right):

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc#newcod...
net/base/mime_util.cc:529: return supported_codecs.find("") !=
supported_codecs.end();
.find(std::string())

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc#newcod...
net/base/mime_util.cc:533: codecs[i].empty())
Do the .empty() check before the .find(), and avoid the lookup.

[DaleCurtis, 2014-07-17 18:41:55]

lgtm

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc
File net/base/mime_util.cc (right):

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc#newcod...
net/base/mime_util.cc:476: { "audio/mpeg", ",mp3" }, // Note: Empty string codec
ID indicates
I'm not convinced it's a good idea, but I wonder if a magic word like ::EMPTY::
would be better in this case.  It wasn't immediately clear that you meant the
prefixed comma was providing the empty string.

[acolwell GONE FROM CHROMIUM, 2014-07-17 18:57:01]

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc
File net/base/mime_util.cc (right):

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc#newcod...
net/base/mime_util.cc:476: { "audio/mpeg", ",mp3" }, // Note: Empty string codec
ID indicates
On 2014/07/17 18:41:55, DaleCurtis wrote:
> I'm not convinced it's a good idea, but I wonder if a magic word like
::EMPTY::
> would be better in this case.  It wasn't immediately clear that you meant the
> prefixed comma was providing the empty string. 

I agree that this isn't awesome, but I fear some sort of "special" string might
lead to other problems if someone is crafty about what they pass to
canPlayType(). I've updated the comment to clarify what is going on with the
comma at the beginning so hopefully that helps.

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc#newcod...
net/base/mime_util.cc:529: return supported_codecs.find("") !=
supported_codecs.end();
On 2014/07/17 18:38:08, Ryan Sleevi wrote:
> .find(std::string())

Done.

https://codereview.chromium.org/400023002/diff/1/net/base/mime_util.cc#newcod...
net/base/mime_util.cc:533: codecs[i].empty())
On 2014/07/17 18:38:08, Ryan Sleevi wrote:
> Do the .empty() check before the .find(), and avoid the lookup.

Done.

[acolwell GONE FROM CHROMIUM, 2014-07-17 18:57:03]

The CQ bit was checked by acolwell@chromium.org

[commit-bot: I haz the power, 2014-07-17 18:59:48]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/acolwell@chromium.org/400023002/40001

[commit-bot: I haz the power, 2014-07-17 23:49:52]

Change committed as 283929