linux aura: Support touch events.

linux aura: Support touch events.

Update coalescing code to make sure touch-update events are also coalesced.

BUG=none
R=dongseong.hwang@intel.com, erg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=238745

[dshwang, 2013-11-27 09:14:28]

Thank you for this CL. non-owner's lgtm


Could I continue my question from
https://chromiumcodereview.appspot.com/14582028/#msg11 ?

On 2013/11/22 19:53:45, dshwang wrote:
> On 2013/11/22 19:51:52, dshwang wrote:
> > On 2013/05/16 22:04:26, I haz the power (commit-bot) wrote:
> > > Change committed as 200636
> > 
> > Hi, may I ask why do not coalesce X touch move events in aura?
> > Thank you in advance.

> I don't remember clearly. I think the coalescing code didn't work correctly
for
> events coming from floating-slave devices?

AFAIK, XI22 touch event can deal with multi touch event. So I don't understand
why we need to care of floating-slave devices.
TouchFactory::UpdateDeviceList(Display* display) decides to receive events from
floating-slave devices.

I think coalescing code is important to reduce touch event latency. Currently,
in x11 code, only mouse events are coalesced. Do you think we need to coalesce
touch events again in the future?

[sadrul, 2013-11-28 17:29:12]

On 2013/11/27 09:14:28, dshwang wrote:
> Thank you for this CL. non-owner's lgtm
> 
> 
> Could I continue my question from
> https://chromiumcodereview.appspot.com/14582028/#msg11 ?
> 
> On 2013/11/22 19:53:45, dshwang wrote:
> > On 2013/11/22 19:51:52, dshwang wrote:
> > > On 2013/05/16 22:04:26, I haz the power (commit-bot) wrote:
> > > > Change committed as 200636
> > > 
> > > Hi, may I ask why do not coalesce X touch move events in aura?
> > > Thank you in advance.
> 
> > I don't remember clearly. I think the coalescing code didn't work correctly
> for
> > events coming from floating-slave devices?
> 
> AFAIK, XI22 touch event can deal with multi touch event. So I don't understand
> why we need to care of floating-slave devices.
> TouchFactory::UpdateDeviceList(Display* display) decides to receive events
from
> floating-slave devices.
> 
> I think coalescing code is important to reduce touch event latency. Currently,
> in x11 code, only mouse events are coalesced. Do you think we need to coalesce
> touch events again in the future?

I have added code for coalescing touch-update events here.

I remember now. In chromeos: we listen to touch-events on both the X11 window,
and the X11 root-window. As a result, each touch event would come in for the
window, then for the root-window, and then the next touch event would be
received. Since we receive the same event on two windows, the coalescing code
would never kick in. That's why removed touch-event coalescing in chromeos. But
for desktop-linux, we listen for touch-events just on the X11 window, and so the
coalescing code works OK.

[sadrul, 2013-11-28 17:29:43]

+erg@ for review.

[dshwang, 2013-12-04 17:37:27]

https://codereview.chromium.org/89413002/diff/60001/ui/views/widget/desktop_a...
File ui/views/widget/desktop_aura/desktop_root_window_host_x11.cc (right):

https://codereview.chromium.org/89413002/diff/60001/ui/views/widget/desktop_a...
ui/views/widget/desktop_aura/desktop_root_window_host_x11.cc:1118: event->type()
== ui::ET_MOUSE_PRESSED) {
s/ET_MOUSE_PRESSED/ET_TOUCH_PRESSED/ ?

why DispatchMouseEvent() does not check event type?

void DesktopRootWindowHostX11::DispatchMouseEvent(ui::MouseEvent* event) {
  if (!g_current_capture || g_current_capture == this) {
    delegate_->OnHostMouseEvent(event);
  } else {
    // Another DesktopRootWindowHostX11 has installed itself as
    // capture. Translate the event's location and dispatch to the other.
    event->ConvertLocationToTarget(root_window_->window(),
                                   g_current_capture->root_window_->window());
    g_current_capture->delegate_->OnHostMouseEvent(event);
  }
}

[sadrul, 2013-12-04 17:57:28]

https://codereview.chromium.org/89413002/diff/60001/ui/views/widget/desktop_a...
File ui/views/widget/desktop_aura/desktop_root_window_host_x11.cc (right):

https://codereview.chromium.org/89413002/diff/60001/ui/views/widget/desktop_a...
ui/views/widget/desktop_aura/desktop_root_window_host_x11.cc:1118: event->type()
== ui::ET_MOUSE_PRESSED) {
On 2013/12/04 17:37:27, dshwang wrote:
> s/ET_MOUSE_PRESSED/ET_TOUCH_PRESSED/ ?

Whoops. Fixed.

> 
> why DispatchMouseEvent() does not check event type?

When a capture is in progress, all mouse events should go to the captured
window. For touch events, if the active touch-points aren't re-targeted when a
capture happens, then the touch events should continue to go to the old target.

[Elliot Glaysher, 2013-12-04 18:36:24]

lgtm

[sadrul, 2013-12-04 20:11:02]

Committed patchset #5 manually as r238745 (presubmit successful).

[dshwang, 2013-12-05 09:15:58]

Thank you for supporting touch event in linux aura. :)