diff --git a/layout/inspector/tests/mochitest.ini b/layout/inspector/tests/mochitest.ini
index e119cf2ce301..a4220d60d1ff 100644
--- a/layout/inspector/tests/mochitest.ini
+++ b/layout/inspector/tests/mochitest.ini
@@ -23,7 +23,6 @@ support-files =
   file_getCSSStyleRules-alternate.html
   getCSSStyleRules-1.css
   getCSSStyleRules-2.css
-[test_getCSSStyleRules_pseudo.html]
 [test_getCSSPseudoElementNames.html]
 [test_getRelativeRuleLine.html]
 [test_get_all_style_sheets.html]
diff --git a/layout/inspector/tests/test_getCSSStyleRules_pseudo.html b/layout/inspector/tests/test_getCSSStyleRules_pseudo.html
deleted file mode 100644
index 097a66baedb7..000000000000
--- a/layout/inspector/tests/test_getCSSStyleRules_pseudo.html
+++ /dev/null
@@ -1,76 +0,0 @@
-<!DOCTYPE html>
-<title>Test getCSSStyleRules for pseudo elements</title>
-<script src="/tests/SimpleTest/SimpleTest.js"></script>
-<link rel="stylesheet" href="/tests/SimpleTest/test.css">
-
-<style>
-#block:before {
-  display: block;
-  content: ":before";
-}
-#block:after {
-  display: block;
-  content: ":after";
-}
-
-#table:before {
-  display: table;
-  content: ":before";
-}
-#table:after {
-  display: table;
-  content: ":after";
-}
-
-#flex:before {
-  display: flex;
-  content: ":before";
-}
-#flex:after {
-  display: flex;
-  content: ":after";
-}
-
-#grid:before {
-  display: grid;
-  content: ":before";
-}
-#grid:after {
-  display: grid;
-  content: ":after";
-}
-</style>
-
-<div id="block">block pseudos</div>
-<div id="table">table pseudos</div>
-<div id="flex">flex pseudos</div>
-<div id="grid">grid pseudos</div>
-
-<script>
-const InspectorUtils = SpecialPowers.InspectorUtils;
-
-function checkPseudoStyleForId(id) {
-  let element = document.getElementById(id);
-
-  let beforeRules = InspectorUtils.getCSSStyleRules(element, ":before");
-  is (beforeRules.length, 1, "Element " + id + ":before has expected number of rules.");
-  let beforeDecl = beforeRules[0].style;
-  is (beforeDecl.content, '":before"', "Element " + id + ":before has expected style content.");
-
-  let afterRules  = InspectorUtils.getCSSStyleRules(element, ":after");
-  is (afterRules.length, 1, "Element " + id + ":after has expected number of rules.");
-  let afterDecl = afterRules[0].style;
-  is (afterDecl.content, '":after"', "Element " + id + ":after has expected style content.");
-}
-
-let idsToCheck = [
-  "block",
-  "table",
-  "flex",
-  "grid",
-];
-
-for (let id of idsToCheck) {
-  checkPseudoStyleForId(id);
-}
-</script>
diff --git a/layout/style/nsComputedDOMStyle.cpp b/layout/style/nsComputedDOMStyle.cpp
index 081c169a2338..82084f82dc51 100644
--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -576,25 +576,21 @@ nsComputedDOMStyle::DoGetComputedStyleNoFlush(Element* aElement,
   if (inDocWithShell &&
       aStyleType == eAll &&
       !aElement->IsHTMLElement(nsGkAtoms::area)) {
-    Element* element = nullptr;
+    nsIFrame* frame = nullptr;
     if (aPseudo == nsCSSPseudoElements::before()) {
-      element = nsLayoutUtils::GetBeforePseudo(aElement);
+      frame = nsLayoutUtils::GetBeforeFrame(aElement);
     } else if (aPseudo == nsCSSPseudoElements::after()) {
-      element = nsLayoutUtils::GetAfterPseudo(aElement);
+      frame = nsLayoutUtils::GetAfterFrame(aElement);
     } else if (!aPseudo) {
-      element = aElement;
+      frame = nsLayoutUtils::GetStyleFrame(aElement);
     }
-
-    if (element) {
-      nsIFrame* primaryFrame = element->GetPrimaryFrame();
-      if (nsIFrame* styleFrame = nsLayoutUtils::GetStyleFrame(element)) {
-        ComputedStyle* result = styleFrame->Style();
-        // Don't use the style if it was influenced by pseudo-elements,
-        // since then it's not the primary style for this element / pseudo.
-        if (!MustReresolveStyle(result)) {
-          RefPtr<ComputedStyle> ret = result;
-          return ret.forget();
-        }
+    if (frame) {
+      ComputedStyle* result = frame->Style();
+      // Don't use the style if it was influenced by pseudo-elements, since then
+      // it's not the primary style for this element / pseudo.
+      if (!MustReresolveStyle(result)) {
+        RefPtr<ComputedStyle> ret = result;
+        return ret.forget();
       }
     }
   }
