[WebMIDI] MIDIManager::create should return non-null object.

[WebMIDI] MIDIManager::create should return non-null object.

enable-web-midi switch can be added for unsupported platforms, for development purpose.
In such case, returning NULL in MIDIManager::create causes a crash.
This CL prevents the crash.

BUG=303596
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=242028

[Takashi Toyoshima, 2013-12-19 07:58:24]

https://codereview.chromium.org/108603004/diff/20001/media/midi/midi_manager.cc
File media/midi/midi_manager.cc (right):

https://codereview.chromium.org/108603004/diff/20001/media/midi/midi_manager....
media/midi/midi_manager.cc:15: class NullMIDIManager : public MIDIManager {
How about just adding default implementations of Initialize(), and
DispatchSendMIDIDate() on MIDIManager class directly in midi_manager.h? Also
NOTREACHED() is needed inside DispatchSendMIDIData().

[yhirano, 2013-12-19 08:21:54]

https://codereview.chromium.org/108603004/diff/20001/media/midi/midi_manager.cc
File media/midi/midi_manager.cc (right):

https://codereview.chromium.org/108603004/diff/20001/media/midi/midi_manager....
media/midi/midi_manager.cc:15: class NullMIDIManager : public MIDIManager {
On 2013/12/19 07:58:24, Takashi Toyoshima (chromium) wrote:
> How about just adding default implementations of Initialize(), and
> DispatchSendMIDIDate() on MIDIManager class directly in midi_manager.h? Also
> NOTREACHED() is needed inside DispatchSendMIDIData().

Done.

[Takashi Toyoshima, 2013-12-19 08:29:06]

lgtm

[yhirano, 2013-12-19 08:34:31]

+dalecurtis for OWNER review.

[DaleCurtis, 2013-12-19 22:05:46]

lgtm

[commit-bot: I haz the power, 2013-12-20 00:44:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/yhirano@chromium.org/108603004/40001

[commit-bot: I haz the power, 2013-12-20 07:27:27]

Change committed as 242028