Backed out changeset 75588bc18622 (bug 1914831) as requested by Emilio for causing unforeseen failures. CLOSED TREE

dom/base/DOMRect.cpp

@@ -148,19 +148,13 @@ JSObject* DOMRectList::WrapObject(JSContext* cx,
 static double RoundFloat(double aValue) { return floor(aValue + 0.5); }
 
 void DOMRect::SetLayoutRect(const nsRect& aLayoutRect) {
-  if (StaticPrefs::dom_rect_legacy_rounding()) {
-    double scale = 65536.0;
-    // Round to the nearest 1/scale units. We choose scale so it can be
-    // represented exactly by machine floating point.
-    double scaleInv = 1 / scale;
-    double t2pScaled = scale / AppUnitsPerCSSPixel();
-    double x = RoundFloat(aLayoutRect.x * t2pScaled) * scaleInv;
-    double y = RoundFloat(aLayoutRect.y * t2pScaled) * scaleInv;
-    return SetRect(
-        float(x), float(y),
-        float(RoundFloat(aLayoutRect.XMost() * t2pScaled) * scaleInv - x),
-        float(RoundFloat(aLayoutRect.YMost() * t2pScaled) * scaleInv - y));
-  }
-  auto rect = CSSRect::FromAppUnits(aLayoutRect);
-  SetRect(rect.x, rect.y, rect.width, rect.height);
+  double scale = 65536.0;
+  // Round to the nearest 1/scale units. We choose scale so it can be
+  // represented exactly by machine floating point.
+  double scaleInv = 1 / scale;
+  double t2pScaled = scale / AppUnitsPerCSSPixel();
+  double x = RoundFloat(aLayoutRect.x * t2pScaled) * scaleInv;
+  double y = RoundFloat(aLayoutRect.y * t2pScaled) * scaleInv;
+  SetRect(x, y, RoundFloat(aLayoutRect.XMost() * t2pScaled) * scaleInv - x,
+          RoundFloat(aLayoutRect.YMost() * t2pScaled) * scaleInv - y);
 }

modules/libpref/init/StaticPrefList.yaml

@@ -2391,13 +2391,6 @@
   value: false
   mirror: always
 
-# Whether the algorithm we use for DOMRect::SetLayoutRect is the legacy one,
-# which is different from what the rest of Gecko uses.
-- name: dom.rect.legacy-rounding
-  type: bool
-  value: false
-  mirror: always
-
 - name: dom.require_user_interaction_for_beforeunload
   type: bool
   value: true