Web MIDI: add MidiScheduler for send() with timestamp

Web MIDI: add MidiScheduler for send() with timestamp

Add MidiScheduler as a common timestamp handling class for all Web MIDI
backend implementations. In this patch, Android backend switches to use
the scheduler to handle timestamp.

BUG=467442, 303596
Committed: https://crrev.com/863f7cf7589acb1d3e08a8fcc2965bc7fb7713a7
Cr-Commit-Position: refs/heads/master@{#323674}

[Takashi Toyoshima, 2015-04-02 13:36:49]

toyoshim@chromium.org changed reviewers:
+ yhirano@chromium.org

[Takashi Toyoshima, 2015-04-02 13:37:31]

toyoshim@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[Takashi Toyoshima, 2015-04-02 13:41:29]

Hi yhirano@

Can you take a look on media/midi?
For m43, I decided to use very naive implementation.
I checked it with NSX-39 at http://yuri.twintail.org/chrome/midit.html on local
Android Chromium build.

dalecurtis@

Can you review build files to add new source files?
Also, do you think we, Web MIDI owners, can have owners permission for these
build files?

[DaleCurtis, 2015-04-02 18:15:04]

media.{gyp,gn} lgtm

[yhirano, 2015-04-03 01:32:16]

lgtm

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.cc
File media/midi/midi_scheduler.cc (right):

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.c...
media/midi/midi_scheduler.cc:28: const base::Closure& weak_closure = base::Bind(
Just curious, does using const reference have any merit in this case?

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h
File media/midi/midi_scheduler.h (right):

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h...
media/midi/midi_scheduler.h:16: class MidiScheduler {
[optional] +final?

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h...
media/midi/midi_scheduler.h:19: ~MidiScheduler();
You don't need an empty destructor.

[Takashi Toyoshima, 2015-04-03 02:35:12]

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.cc
File media/midi/midi_scheduler.cc (right):

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.c...
media/midi/midi_scheduler.cc:28: const base::Closure& weak_closure = base::Bind(
I did not have a strong reason here, but just followed base/ style, e.g.,
base/task/cancelable_task_tracker.cc.

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h
File media/midi/midi_scheduler.h (right):

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h...
media/midi/midi_scheduler.h:16: class MidiScheduler {
On 2015/04/03 01:32:16, yhirano wrote:
> [optional] +final?

Done.

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h...
media/midi/midi_scheduler.h:19: ~MidiScheduler();
Without this, compiler reports an error like,

../../media/midi/midi_scheduler.h:16:1: error: [chromium-style] Complex
class/struct needs an explicit out-of-line destructor.

[Takashi Toyoshima, 2015-04-03 02:39:04]

The CQ bit was checked by toyoshim@chromium.org

[Takashi Toyoshima, 2015-04-03 02:39:05]

The patchset sent to the CQ was uploaded after l-g-t-m from
dalecurtis@chromium.org, yhirano@chromium.org
Link to the patchset: https://codereview.chromium.org/1052983002/#ps20001
(title: "final")

[yhirano, 2015-04-03 03:26:39]

Still lgtm

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h
File media/midi/midi_scheduler.h (right):

https://codereview.chromium.org/1052983002/diff/1/media/midi/midi_scheduler.h...
media/midi/midi_scheduler.h:19: ~MidiScheduler();
On 2015/04/03 02:35:11, Takashi Toyoshima (chromium) wrote:
> Without this, compiler reports an error like,
> 
> ../../media/midi/midi_scheduler.h:16:1: error: [chromium-style] Complex
> class/struct needs an explicit out-of-line destructor.

Oh, sorry, you're right.

[commit-bot: I haz the power, 2015-04-03 04:43:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1052983002/20001

[commit-bot: I haz the power, 2015-04-03 07:53:51]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-03 20:34:41]

Patchset 2 (id:??) landed as
https://crrev.com/863f7cf7589acb1d3e08a8fcc2965bc7fb7713a7
Cr-Commit-Position: refs/heads/master@{#323674}