Backed out changeset 80c0c730e1aa (bug 1729894) for causing mochitest failures on browser_styleeditor_autocomplete.js. CLOSED TREE

devtools/shared/css/generated/properties-db.js

@@ -3401,31 +3401,6 @@ exports.CSS_PROPERTIES = {
       "unset"
     ]
   },
-  "backdrop-filter": {
-    "isInherited": false,
-    "subproperties": [
-      "backdrop-filter"
-    ],
-    "supports": [],
-    "values": [
-      "blur",
-      "brightness",
-      "contrast",
-      "drop-shadow",
-      "grayscale",
-      "hue-rotate",
-      "inherit",
-      "initial",
-      "invert",
-      "none",
-      "opacity",
-      "revert",
-      "saturate",
-      "sepia",
-      "unset",
-      "url"
-    ]
-  },
   "backface-visibility": {
     "isInherited": false,
     "subproperties": [

gfx/thebes/gfxPlatform.cpp

@@ -2518,6 +2518,11 @@ void gfxPlatform::InitWebRenderConfig() {
   bool prefEnabled = WebRenderPrefEnabled();
   bool envvarEnabled = WebRenderEnvvarEnabled();
 
+  // This would ideally be in the nsCSSProps code
+  // but nsCSSProps is initialized before gfxPlatform
+  // so it has to be done here.
+  gfxVars::AddReceiver(&nsCSSProps::GfxVarReceiver());
+
   // WR? WR+   => means WR was enabled via gfx.webrender.all.qualified on
   //              qualified hardware
   // WR! WR+   => means WR was enabled via gfx.webrender.{all,enabled} or
@@ -2532,6 +2537,9 @@ void gfxPlatform::InitWebRenderConfig() {
     // later in this function. For other processes we still want to report
     // the state of the feature for crash reports.
     if (gfxVars::UseWebRender()) {
+      // gfxVars doesn't notify receivers when initialized on content processes
+      // we need to explicitly recompute backdrop-filter's enabled state here.
+      nsCSSProps::RecomputeEnabledState("layout.css.backdrop-filter.enabled");
       reporter.SetSuccessful();
     }
     return;

layout/style/nsCSSProps.cpp

@@ -76,6 +76,10 @@ void nsCSSProps::RecomputeEnabledState(const char* aPref, void*) {
 #else
       gPropertyEnabled[pref->mPropID] = Preferences::GetBool(pref->mPref);
 #endif
+      if (pref->mPropID == eCSSProperty_backdrop_filter) {
+        gPropertyEnabled[pref->mPropID] &=
+            gfx::gfxVars::GetUseWebRenderOrDefault();
+      }
     }
   }
   MOZ_ASSERT(foundPref);
@@ -212,4 +216,40 @@ bool nsCSSProps::gPropertyEnabled[eCSSProperty_COUNT_with_aliases] = {
 #undef IS_ENABLED_BY_DEFAULT
 };
 
+/**
+ * A singleton class to register as a receiver for gfxVars.
+ * Updates the state of backdrop-filter's pref if the gfx
+ * WebRender var changes state.
+ */
+class nsCSSPropsGfxVarReceiver final : public gfx::gfxVarReceiver {
+  constexpr nsCSSPropsGfxVarReceiver() = default;
+
+  // WebRender's last known enabled state.
+  static bool sLastKnownUseWebRender;
+  static nsCSSPropsGfxVarReceiver sInstance;
+
+ public:
+  static gfx::gfxVarReceiver& GetInstance() { return sInstance; }
+
+  void OnVarChanged(const gfx::GfxVarUpdate&) override {
+    bool enabled = gfxVars::UseWebRender();
+    if (sLastKnownUseWebRender != enabled) {
+      sLastKnownUseWebRender = enabled;
+      nsCSSProps::RecomputeEnabledState("layout.css.backdrop-filter.enabled");
+    }
+  }
+};
+
+/* static */
+nsCSSPropsGfxVarReceiver nsCSSPropsGfxVarReceiver::sInstance =
+    nsCSSPropsGfxVarReceiver();
+
+/* static */
+bool nsCSSPropsGfxVarReceiver::sLastKnownUseWebRender = false;
+
+/* static */
+gfx::gfxVarReceiver& nsCSSProps::GfxVarReceiver() {
+  return nsCSSPropsGfxVarReceiver::GetInstance();
+}
+
 #include "nsCSSPropsGenerated.inc"

modules/libpref/init/StaticPrefList.yaml

@@ -6856,7 +6856,7 @@
 # Is support for CSS backdrop-filter enabled?
 - name: layout.css.backdrop-filter.enabled
   type: bool
-  value: @IS_EARLY_BETA_OR_EARLIER@
+  value: false
   mirror: always
 
 # Should stray control characters be rendered visibly?