Remove workarounds for old DOM APIs prior ot event.movementX/Y - #27341
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Inline `event.movementX` and `event.movementY` directly into
`calculateMouseEvent` in `libbrowser.js`, removing the `getMovementX`
and `getMovementY` helper methods from `LibraryBrowser`.
Remove references to `mozMovementX`, `webkitMovementX`, `mozMovementY`,
and `webkitMovementY` from `libbrowser.js` and `libsdl.js`. Also update
`libhtml5.js` and `libsdl.js` to use standard dot notation
(`e.movementX`, `event.movementX`) instead of bracket notation across
all mouse event handling.
These prefixed properties and their workarounds (`if ('mozMovementX' in
event)`) were added between 2012 and 2013 for early implementations of
the W3C Pointer Lock API to address Firefox bugs #750111 and #764498.
This is safe to remove because:
1. `MouseEvent.movementX` and `MouseEvent.movementY` became standard
unprefixed properties in Firefox 41 (2015) and Chrome 37 (2014).
2. Emscripten's minimum supported browser versions
(`MIN_FIREFOX_VERSION` and `MIN_CHROME_VERSION`) are well beyond when
unprefixed `movementX` became universal across all engines.
3. The vendor-prefixed properties (`mozMovementX`, `webkitMovementX`)
have been removed from modern browser engines.
4. Bugzilla bugs #750111 (`mozMovementX is transient and becomes zero
later`) and #764498 (`movementX and movementY have the wrong value for
mousedown and mouseup`) were both resolved in 2012 (Firefox 15).
See: https://bugzilla.mozilla.org/show_bug.cgi?id=750111
See: https://bugzilla.mozilla.org/show_bug.cgi?id=764498
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Inline
event.movementXandevent.movementYdirectly intocalculateMouseEventinlibbrowser.js, removing thegetMovementXandgetMovementYhelper methods fromLibraryBrowser.Remove references to
mozMovementX,webkitMovementX,mozMovementY, andwebkitMovementYfromlibbrowser.jsandlibsdl.js. Also updatelibhtml5.jsandlibsdl.jsto use standard dot notation (e.movementX,event.movementX) instead of bracket notation across all mouse event handling.These prefixed properties and their workarounds (
if ('mozMovementX' in event)) were added between 2012 and 2013 for early implementations of the W3C Pointer Lock API to address Firefox bugs #750111 and #764498.This is safe to remove because:
MouseEvent.movementXandMouseEvent.movementYbecame standard unprefixed properties in Firefox 41 (2015) and Chrome 37 (2014).MIN_FIREFOX_VERSIONandMIN_CHROME_VERSION) are well beyond when unprefixedmovementXbecame universal across all engines.mozMovementX,webkitMovementX) have been removed from modern browser engines.mozMovementX is transient and becomes zero later) and #764498 (movementX and movementY have the wrong value for mousedown and mouseup) were both resolved in 2012 (Firefox 15).See: https://bugzilla.mozilla.org/show_bug.cgi?id=750111
See: https://bugzilla.mozilla.org/show_bug.cgi?id=764498
See: https://bugzilla.mozilla.org/show_bug.cgi?id=782777