Bug 1736049 - Stop calling [[NSCursor currentCursor] set] on every …

…mouse move. r=emilio

This was only necessary when we had binary plug-ins overriding the cursor from under us.
We no longer support plug-ins.

Calling -[NSCursor set] has a performance cost on macOS Monterey when
cursor accessibility coloring is enabled, so we want to avoid calling it
unnecessarily. It also leaks memory in the current Monterey Beta (see
bug 1735345), so calling it less often will leak less memory.

I have checked the testcases of bug 496601 and of bug 1423275, they still
work as expected with this fix.

Differential Revision: https://phabricator.services.mozilla.com/D128612

widget/cocoa/nsCursorManager.mm

@@ -211,11 +211,6 @@ - (nsresult)setNonCustomCursor:(const nsIWidget::Cursor&)aCursor {
 - (nsresult)setMacCursor:(nsMacCursor*)aMacCursor {
   NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
 
-  // Some plugins mess with our cursors and set a cursor that even
-  // [NSCursor currentCursor] doesn't know about. In case that happens, just
-  // reset the state.
-  [[NSCursor currentCursor] set];
-
   nsCursor oldType = [mCurrentMacCursor type];
   nsCursor newType = [aMacCursor type];
   if (oldType != newType) {
@@ -245,7 +240,6 @@ - (nsresult)setCustomCursor:(const nsIWidget::Cursor&)aCursor
 
   // As the user moves the mouse, this gets called repeatedly with the same aCursorImage
   if (sCurrentCursor == aCursor && sCurrentCursorScaleFactor == scaleFactor && mCurrentMacCursor) {
-    [self setMacCursor:mCurrentMacCursor];
     return NS_OK;
   }