Monkey patch the Leaflet layer selector to work in Mobile Safari

[jwalgran]

Overview

Tapping on the layers control in Mobile Safari was not opening the layer selector. I was not able to reproduce this issue in a separate test application, only within OTM.

After much trial and error I discovered that changing this line

  L.DomEvent.on(el, L.Draggable.START.join(' '), stop);

to

  L.DomEvent.on(container, 'mousedown', stop);

in DomEvent.disableClickPropagation resolved the issue. Effectively, this prevents the touchstart event from being stopped.

I opted to implement this as a runtime patch applied within MapManager instead of a global patch to the Leaflet source because there are no other Leaflet behaviors that are known to be broken in Mobile Safari and I did not want to risk introducing a regression in some other event handling.

I minimized the chance of forgetting about this patch if/when we upgrade our version of Leaflet by adding a comment to package.json.

Connects #3250

Testing Instructions

Setup

• Ensure that your development server is accessible from other machines on the network.
• Obtain an iOS device for testing (hardware or simulator). Browse https://www.opentreemap.org/phillytreemap in Mobile Safari and verify that tapping on the layer selector does not work.

Test

• Run vagrant provision app and verify that it completes without error.
• Browse an instance on your development server in Mobile Safari and verify that the layer selector works.

[jwalgran]

The comment in the dependency section of the package.json file did not work. I am going to try moving it up to the top level.

[coveralls]

Coverage remained the same at 83.796% when pulling e89ebf259a503b9b7f271fe312fc8112af3cc9c5 on jcw/mobile-safari-layer-selector into d483bfb436a9014fdb2a199f09039314302f6629 on develop.

[jwalgran]

I force pushed a commit that resolved the build failure.

[jwalgran]

Thanks for the review.