Bug 1623476 - Disable zoom-to-focused-input behaviour in clipboard tests. r=kats

The tests don't have a reliable mechanism to wait for a potential zoom
animation to end, leading to flakiness due to a zoom animation form a previous
sub-case interfering with the current sub-case.

Differential Revision: https://phabricator.services.mozilla.com/D67522

--HG--
extra : moz-landing-system : lando

dom/base/nsDOMWindowUtils.cpp

@@ -2475,6 +2475,10 @@ nsDOMWindowUtils::DisableApzForElement(Element* aElement) {
 
 NS_IMETHODIMP
 nsDOMWindowUtils::ZoomToFocusedInput() {
+  if (!Preferences::GetBool("apz.zoom-to-focused-input.enabled")) {
+    return NS_OK;
+  }
+
   nsIWidget* widget = GetWidget();
   if (!widget) {
     return NS_OK;

dom/base/test/useractivation/mochitest.ini

@@ -5,6 +5,8 @@ support-files =
   file_iframe_check_user_activation.html
   file_iframe_consume_user_activation.html
   file_clipboard_common.js
+prefs =
+  apz.zoom-to-focused-input.enabled=false
 
 [test_useractivation_has_been_activated.html]
 [test_useractivation_transient.html]

modules/libpref/init/all.js

@@ -586,6 +586,8 @@ pref("media.audiograph.single_thread.enabled", true);
 pref("apz.overscroll.stop_velocity_threshold", "0.01");
 pref("apz.overscroll.stretch_factor", "0.35");
 
+pref("apz.zoom-to-focused-input.enabled", true);
+
 #ifdef XP_MACOSX
   // Whether to run in native HiDPI mode on machines with "Retina"/HiDPI
   // display.