Unable to reproduce this issue on Windows-10 (Dell precision) touch screen machine using chrome latest Dev #57.0.2948.0.

This issue might be specific to Linux machine, currently touch screen hardware not available with chrome-TE HYD team, passing it to MTV team to look in to it further.

Thanks!

I can reproduce the issue now in a VirtualBox running Ubuntu 16.04 (my build system) with a native build of Chromium 57.02948.0. When setting --touch-devices to the emulated mouse.

Here are the details:

chromium@chromium:~/chromium/src/out/native$ xinput list
⎡ Virtual core pointer                    	id=2	[master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer              	id=4	[slave  pointer  (2)]
⎜   ↳ VirtualBox mouse integration            	id=9	[slave  pointer  (2)]
⎜   ↳ ImExPS/2 Generic Explorer Mouse         	id=11	[slave  pointer  (2)]
⎣ Virtual core keyboard                   	id=3	[master keyboard (2)]
    ↳ Virtual core XTEST keyboard             	id=5	[slave  keyboard (3)]
    ↳ Power Button                            	id=6	[slave  keyboard (3)]
    ↳ Sleep Button                            	id=7	[slave  keyboard (3)]
    ↳ Video Bus                               	id=8	[slave  keyboard (3)]
    ↳ AT Translated Set 2 keyboard            	id=10	[slave  keyboard (3)]
chromium@chromium:~/chromium/src/out/native$ ./chrome --touch-devices=11 './chrome --touch-devices=11 https://mdn.mozillademos.org/en-US/docs/Web/API/Touch_events$samples/Example?revision=1168311'

Chromium 55.0.2883.87, which is included in Ubuntu 16.04 distro, behaves same.

I am aware that "ImExPS/2 Generic Explorer Mouse" is not a proper touch device, but behavior is exactly same with the used touch devices.

Please find attached the details about the used touch device. The only potential issue I can see with it is that it does not support the event ABS_MT_DISTANCE. 

Deleted: touch_screen_events.txt 2.3 KB

touch_screen_events.txt 2.3 KB View Download

According to the following description from https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt

ABS_MT_DISTANCE

The distance, in surface units, between the contact and the surface. Zero
distance means the contact is touching the surface. A positive number means
the contact is hovering above the surface.

ABS_MT_DISTANCE should not be required for this scenario.

Mustaq, could you help triage, I don't have a Linux touchscreen. 

When running the same VirtualBox guest on a Windows host with a touch screen and pointing --touch-devices to "VirtualBox USB Multi-Touch" (see attached details), the test works fine. That means that there seems to be no general issue with Chromium, but some specific issue with the original touch screen.

Deleted: vb-usb-multi-touch.txt 2.5 KB

vb-usb-multi-touch.txt 2.5 KB View Download

Reporter can you still reproduce this issue? Is it only happening in a Virtual Box Linux guest? I do recall from the last time I connected a touch screen to my Linux it touch interaction with the content and Chrome worked just fine.

With the additional command-line argument "--touch-events=enabled", the problem was solved.

Assigning to lanwei@: ptal.  May be we have a redundant touch-event check around x11 that is causing this?