Maps do not pan in Chrome 55 or Microsoft Edge

[dtapuska]

We shipped Pointer Events in Chrome 55 and discovered that this library adds pointer event listeners and touch event listeners.

I believe there are two problems with the code

1. ol2/lib/OpenLayers/Events.js

   Line 676 in 75716be

   OpenLayers.Event.observe(element, type, this.eventHandler

   seems to add touch event listeners. Perhaps it should do something like:

            if ((touchModel === this.TOUCH_MODEL_POINTER ||
                    touchModel === this.TOUCH_MODEL_MSPOINTER) &&
                    type.indexOf('touch') === 0) {
                this.addPointerTouchListener(element, type, this.eventHandler);
            } else {
               OpenLayers.Event.observe(element, type, this.eventHandler);
            }

Instead of always adding the event handler?

2. A touch-action: none needs to be applied to perhaps the olMapViewport
   https://github.com/openlayers/ol2/blob/master/theme/default/style.css#L8

@dracos I believe these fixes will address the issue you logged against Chromium

[dtapuska]

@NavidZ @mustaqahmed FYI

[dracos]

Oh, great, thank you! I have tested this on our use of OL2 on https://github.com/mysociety/fixmystreet and have found that I need to put the touch-action: none on olMap, not olMapViewport, for it to work (it did work on olMapViewport on the cut-down version I supplied, sorry, I’m not sure what would cause the difference) – putting it on olMapViewport led to it registering the start of a drag but then stopping after only a pixel or two movement.
I’ve put the code above in a PR at #1511, and will deploy it locally in a few minutes...