Add SchedulePollEvents and PollEvents

Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager queries devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org

Committed: https://crrev.com/95d513d3be6520a86f74105ccb95cedf3f849e92
Cr-Commit-Position: refs/heads/master@{#414970}

[shaobo.yan, 2016-08-22 02:29:57]

Hi, bajones, This is my first patch for chromium, PTAL,and may be I need request
try bots run for this patch ? thx.

[shaobo.yan, 2016-08-23 22:22:27]

Description was changed from

==========
Add SchedulePollEvents and PollEvents in abstract layer of vr device

Since WebVR spec already has VRDisplayEvent and define several type of
event handler, device needs to query the vr device status and generate
event.

These two methods are charge for this. VRDeviceManager query device by
invoke PollEvents and each type of device will implement the PollEvent.

BUG=389343
R=bajones@chromium.org
==========

to

==========
Add SchedulePollEvents and PollEvents in abstract layer of vr device

Since WebVR spec already has VRDisplayEvent and define several type of
event handler, device needs to query the vr device status and generate
event.

These two methods are charge for this. VRDeviceManager query device by
invoke PollEvents and each type of device will implement the PollEvent.

BUG=389343
R=bajones@chromium.org
==========

[yunchao, 2016-08-24 09:22:14]

On 2016/08/22 02:29:57, shaobo.yan wrote:
> Hi, bajones, This is my first patch for chromium, PTAL,and may be I need
request
> try bots run for this patch ? thx.

Hi Brandon, Shaobo is a team member from my team. He focused on VR/WebVR related
area since last year. Now he wants to spend some time in WebVR in Upstream
Chromium. For example, he can help to take some common tasks, and integrate
Intel VR device with Chromium WebVR in future, etc. 

This is his first patch, could you help to review it? Thanks a lot!

[shaobo.yan, 2016-08-25 00:45:11]

Description was changed from

==========
Add SchedulePollEvents and PollEvents in abstract layer of vr device

Since WebVR spec already has VRDisplayEvent and define several type of
event handler, device needs to query the vr device status and generate
event.

These two methods are charge for this. VRDeviceManager query device by
invoke PollEvents and each type of device will implement the PollEvent.

BUG=389343
R=bajones@chromium.org
==========

to

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
querys devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org
==========

[shaobo.yan, 2016-08-25 00:46:07]

shaobo.yan@intel.com changed reviewers:
+ bshe@chromium.org

[shaobo.yan, 2016-08-25 00:46:34]

Description was changed from

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
querys devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org
==========

to

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
queries devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org
==========

[shaobo.yan, 2016-08-25 05:05:18]

shaobo.yan@intel.com changed reviewers:
+ girard@chromium.org, hendrikw@chromium.org, kbr@chromium.org

[bajones, 2016-08-25 16:11:30]

Apologies for how long this has taken to review, and thanks for contributing!
Code LGTM with one small request, but there's a few things to keep in mind with
this code going forward.

I think we probably don't want to be scheduling the polls on the main browser
thread, so this should probably end up in it's own thread. That might get
tricky, because depending on the VR API in use they may not be thread safe and
polling events on one thread and poses on another won't fly. Since the code
isn't actually being called here it's not a problem just yet, but it'll be
something to watch out for in future CLs.

The one request I would have is to provide a function to stop polling events,
and call that in the destructor instead. I anticipate we'll want to be starting
and stopping event polling in response to various page states.

[shaobo.yan, 2016-08-26 04:25:10]

On 2016/08/25 16:11:30, bajones wrote:
> Apologies for how long this has taken to review, and thanks for contributing!
> Code LGTM with one small request, but there's a few things to keep in mind
with
> this code going forward.
> 
> I think we probably don't want to be scheduling the polls on the main browser
> thread, so this should probably end up in it's own thread. That might get
> tricky, because depending on the VR API in use they may not be thread safe and
> polling events on one thread and poses on another won't fly. Since the code
> isn't actually being called here it's not a problem just yet, but it'll be
> something to watch out for in future CLs.
> 
> The one request I would have is to provide a function to stop polling events,
> and call that in the destructor instead. I anticipate we'll want to be
starting
> and stopping event polling in response to various page states.

Hi, bajones, thx for your reviewing ! I've updated the patch. PTAL.

But here are some point I couldn't understand clearly, hope you could help me
work this out:
   1. I don't know the exactly meaning of "polling events on one thread and
poses on another won't fly", especially poses on another part.
   2. Does the second paragragh means that it is better to apply a new thread
for schedulePollEvent running on and browser thread uses method like 'start' to
post a cancelable task and uses 'stop' to cancel the task ?

If any mistake, pls correct me :) Thx for your time and review again.

[shaobo.yan, 2016-08-29 00:22:47]

On 2016/08/26 04:25:10, shaobo.yan wrote:
> On 2016/08/25 16:11:30, bajones wrote:
> > Apologies for how long this has taken to review, and thanks for
contributing!
> > Code LGTM with one small request, but there's a few things to keep in mind
> with
> > this code going forward.
> > 
> > I think we probably don't want to be scheduling the polls on the main
browser
> > thread, so this should probably end up in it's own thread. That might get
> > tricky, because depending on the VR API in use they may not be thread safe
and
> > polling events on one thread and poses on another won't fly. Since the code
> > isn't actually being called here it's not a problem just yet, but it'll be
> > something to watch out for in future CLs.
> > 
> > The one request I would have is to provide a function to stop polling
events,
> > and call that in the destructor instead. I anticipate we'll want to be
> starting
> > and stopping event polling in response to various page states.
> 
> Hi, bajones, thx for your reviewing ! I've updated the patch. PTAL.
> 
> But here are some point I couldn't understand clearly, hope you could help me
> work this out:
>    1. I don't know the exactly meaning of "polling events on one thread and
> poses on another won't fly", especially poses on another part.
>    2. Does the second paragragh means that it is better to apply a new thread
> for schedulePollEvent running on and browser thread uses method like 'start'
to
> post a cancelable task and uses 'stop' to cancel the task ?
> 
> If any mistake, pls correct me :) Thx for your time and review again.

ping bajones@

[bajones, 2016-08-29 01:06:01]

On 2016/08/26 04:25:10, shaobo.yan wrote:
> Hi, bajones, thx for your reviewing ! I've updated the patch. PTAL.
> 
> But here are some point I couldn't understand clearly, hope you could help me
> work this out:
>    1. I don't know the exactly meaning of "polling events on one thread and
> poses on another won't fly", especially poses on another part.

Simply put: Some VR SDKs may not be thread safe. If the event polling is
threaded future CLs will need to be aware of that. Doesn't really affect this
CL.

>    2. Does the second paragragh means that it is better to apply a new thread
> for schedulePollEvent running on and browser thread uses method like 'start'
to
> post a cancelable task and uses 'stop' to cancel the task ?

Yes. But again, that's something for a future CL.

Updated patch LGTM as well. Feel free to send to the commit queue.

[shaobo.yan, 2016-08-29 01:47:24]

The CQ bit was checked by shaobo.yan@intel.com

[commit-bot: I haz the power, 2016-08-29 01:47:40]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-29 03:54:47]

Description was changed from

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
queries devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org
==========

to

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
queries devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org
==========

[commit-bot: I haz the power, 2016-08-29 03:54:48]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-08-29 03:57:28]

Description was changed from

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
queries devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org
==========

to

==========
Add SchedulePollEvents and PollEvents

Since WebVR spec already has VRDisplayEvent and definess several types of
events. Devices needs to be queried to get status and generate events.

These two methods enable the mechanism to query vr device. VRDeviceManager
queries devices by
invoke PollEvents and vr device will implement PollEvent to do this.

BUG=389343
R=bajones@chromium.org

Committed: https://crrev.com/95d513d3be6520a86f74105ccb95cedf3f849e92
Cr-Commit-Position: refs/heads/master@{#414970}
==========

[commit-bot: I haz the power, 2016-08-29 03:57:29]

Patchset 2 (id:??) landed as
https://crrev.com/95d513d3be6520a86f74105ccb95cedf3f849e92
Cr-Commit-Position: refs/heads/master@{#414970}