Bug 1516867 - Clamp selection color saturation between 0 and 255 in n…

…sLookAndFeel.mm. r=mstange

Differential Revision: https://phabricator.services.mozilla.com/D15500

--HG--
extra : rebase_source : 2f7ced5f752a87b7df61aa0756b9315ca264ecab
extra : amend_source : 5f0fb6dc3ca07d34fd2b160490a1ade9c5daa424

widget/cocoa/nsLookAndFeel.mm

@@ -157,7 +157,7 @@ static nscolor GetColorFromNSColorWithAlpha(NSColor* aColor, float alpha)
   if (sat > 0) {
     // The color is not a shade of grey, restore the saturation taken away by
     // the transparency.
-    sat = sat * factor;
+    sat = mozilla::clamped(sat * factor, 0, 255);
   } else {
     // The color is a shade of grey, find the value that looks equivalent
     // on a white background with the given opacity.