Bug 1622111 - Convert dom.animations.offscreen-throttling to static pref. r=njn

Converts dom.animations.offscreen-throttling to a static pref and removes the static function used to create the varcache pref.

Differential Revision: https://phabricator.services.mozilla.com/D67182

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

dom/animation/AnimationUtils.cpp

@@ -9,7 +9,6 @@
 #include "mozilla/dom/Document.h"
 #include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/EffectSet.h"
-#include "mozilla/Preferences.h"
 #include "nsDebug.h"
 #include "nsAtom.h"
 #include "nsIContent.h"
@@ -58,20 +57,6 @@ Document* AnimationUtils::GetDocumentFromGlobal(JSObject* aGlobalObject) {
   return win->GetDoc();
 }
 
-/* static */
-bool AnimationUtils::IsOffscreenThrottlingEnabled() {
-  static bool sOffscreenThrottlingEnabled;
-  static bool sPrefCached = false;
-
-  if (!sPrefCached) {
-    sPrefCached = true;
-    Preferences::AddBoolVarCache(&sOffscreenThrottlingEnabled,
-                                 "dom.animations.offscreen-throttling");
-  }
-
-  return sOffscreenThrottlingEnabled;
-}
-
 /* static */
 bool AnimationUtils::FrameHasAnimatedScale(const nsIFrame* aFrame) {
   EffectSet* effectSet = EffectSet::GetEffectSetForFrame(

dom/animation/AnimationUtils.h

@@ -73,11 +73,6 @@ class AnimationUtils {
    */
   static Document* GetDocumentFromGlobal(JSObject* aGlobalObject);
 
-  /**
-   * Checks if offscreen animation throttling is enabled.
-   */
-  static bool IsOffscreenThrottlingEnabled();
-
   /**
    * Returns true if the given frame has an animated scale.
    */

dom/animation/KeyframeEffect.cpp

@@ -1838,7 +1838,7 @@ void KeyframeEffect::SetAnimation(Animation* aAnimation) {
 }
 
 bool KeyframeEffect::CanIgnoreIfNotVisible() const {
-  if (!AnimationUtils::IsOffscreenThrottlingEnabled()) {
+  if (StaticPrefs::dom_animations_offscreen_throttling()) {
     return false;
   }
 

modules/libpref/init/StaticPrefList.yaml

@@ -1329,6 +1329,12 @@
   value: false
   mirror: always
 
+# Checks if offscreen animation throttling is enabled.
+- name: dom.animations.offscreen-throttling
+  type: bool
+  value: true
+  mirror: always
+
 # Is support for automatically removing replaced filling animations enabled?
 - name: dom.animations-api.autoremove.enabled
   type: bool

modules/libpref/init/all.js

@@ -2583,9 +2583,6 @@ pref("layout.testing.overlay-scrollbars.always-visible", false);
 // pref to control whether layout warnings that are hit quite often are enabled
 pref("layout.spammy_warnings.enabled", false);
 
-// Pref to throttle offsreen animations
-pref("dom.animations.offscreen-throttling", true);
-
 // if true, allow plug-ins to override internal imglib decoder mime types in full-page mode
 pref("plugin.override_internal_types", false);