1873142 - synthesizePlainDragAndDrop should consider mobile viewport and drag threshold

Status: NEW

(Core :: DOM: Events, defect)

Description

[Makoto Kato [:m_kato]]

Actually mochitest seems not to use width=device-width in <meta name="viewport">, so it runs on mobile viewport. Also, drag threshold is 25 pixels on GeckoView. (I think that this is better value for touch operation, but I don't know this is better value for mouse operation). It will require 34 pixels (25 * (960/720) = 34) to start drag operation on our CI's emulator.

Now, synthesizePlainDragAndDrop uses 9 pixels as drag threshold (stepX and stepY), but this is too small to start drag operation on GeckoView.

Bug 1586471 will add a workaround by modifying drag threshold prefs. This synthesizePlainDragAndDrop should consider for mobile situation without workaround.

Comment 1

[Sean Feng [:sefeng211]]

Not sure who owns synthesizePlainDragAndDrop, but drag and drop is our thing.