perf: Disable msd physics by default to improve scrolling, b=no-bug, c=no-component

Author: mr-cheffy

src/browser/app/profile/smoothscroll.inc

@@ -0,0 +1,14 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+pref("general.smoothScroll.currentVelocityWeighting", "0.15");
+pref("general.smoothScroll.stopDecelerationWeighting", "0.6");
+pref("mousewheel.min_line_scroll_amount", 10);
+pref("general.smoothScroll.mouseWheel.durationMinMS", 80);
+pref("general.smoothScroll.msdPhysics.continuousMotionMaxDeltaMS", 12);
+pref("general.smoothScroll.msdPhysics.motionBeginSpringConstant", 600);
+pref("general.smoothScroll.msdPhysics.regularSpringConstant", 650);
+pref("general.smoothScroll.msdPhysics.slowdownMinDeltaMS", 25);
+pref("general.smoothScroll.msdPhysics.slowdownSpringConstant", 250);
+pref("mousewheel.default.delta_multiplier_y", 200);

src/browser/app/profile/zen-browser.js

@@ -36,5 +36,9 @@ pref('toolkit.legacyUserProfileCustomizations.stylesheets', true);
 
 #include features.inc
 
+#ifndef XP_MACOSX
+#include smoothscroll.inc
+#endif
+
 #include performance.inc
 #include pip.inc