Fix a typo in CounterStyle when handling prefix and suffix

Bug: 687225
Change-Id: I4d74f4043d9ab3b2391fff602809b6b30aa0ea3b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626921
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Auto-Submit: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843174}

third_party/blink/renderer/core/css/counter_style.cc

@@ -328,7 +328,7 @@ void CounterStyle::ResolveExtends(const CounterStyle& extended) {
   if (!style_rule_->GetPrefix())
     prefix_ = extended.prefix_;
   if (!style_rule_->GetSuffix())
-    prefix_ = extended.suffix_;
+    suffix_ = extended.suffix_;
 
   // TODO(crbug.com/687225): Implement 'speak-as'.
 }

third_party/blink/renderer/core/css/counter_style_test.cc

@@ -441,4 +441,16 @@ TEST_F(CounterStyleTest, ExtremeValuesFixed) {
   EXPECT_EQ("B", fixed.GenerateRepresentation(std::numeric_limits<int>::max()));
 }
 
+TEST_F(CounterStyleTest, PrefixAndSuffix) {
+  const CounterStyle& base = AddCounterStyle(
+      "base", "system: symbolic; symbols: A; prefix: X; suffix: Y;");
+  EXPECT_EQ("X", base.GetPrefix());
+  EXPECT_EQ("Y", base.GetSuffix());
+
+  const CounterStyle& extended =
+      AddCounterStyle("extended", "system: extends base");
+  EXPECT_EQ("X", extended.GetPrefix());
+  EXPECT_EQ("Y", extended.GetSuffix());
+}
+
 }  // namespace blink