Implement custom 'negative' values for @counter-style

Bug: 687225
Change-Id: I92de1e68336d49393ae7609e745cfbd749c0db7d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2585904Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835917}

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

@@ -237,6 +237,15 @@ CounterStyle::CounterStyle(const StyleRuleCounterStyle& rule)
     }
   }
 
+  if (const CSSValue* negative = rule.GetNegative()) {
+    if (const CSSValuePair* pair = DynamicTo<CSSValuePair>(negative)) {
+      negative_prefix_ = SymbolToString(pair->First());
+      negative_suffix_ = SymbolToString(pair->Second());
+    } else {
+      negative_prefix_ = SymbolToString(*negative);
+    }
+  }
+
   // TODO(crbug.com/687225): Implement and populate other fields.
 }
 
@@ -255,6 +264,11 @@ void CounterStyle::ResolveExtends(const CounterStyle& extended) {
   if (system_ == CounterStyleSystem::kAdditive)
     additive_weights_ = extended.additive_weights_;
 
+  if (!style_rule_->GetNegative()) {
+    negative_prefix_ = extended.negative_prefix_;
+    negative_suffix_ = extended.negative_suffix_;
+  }
+
   // TODO(crbug.com/687225): Implement and populate other fields.
 }
 
@@ -322,12 +336,14 @@ String CounterStyle::GenerateRepresentation(int value) const {
     return fallback_style_->GenerateRepresentation(value);
   }
 
-  // TODO(crbug.com/687225): Implement non-default 'pad' and 'negative' values.
+  // TODO(crbug.com/687225): Implement non-default 'pad' value.
 
   StringBuilder result;
   if (NeedsNegativeSign(value))
-    result.Append("-");
+    result.Append(negative_prefix_);
   result.Append(initial_representation);
+  if (NeedsNegativeSign(value))
+    result.Append(negative_suffix_);
   return result.ToString();
 }
 

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

@@ -97,6 +97,9 @@ class CORE_EXPORT CounterStyle final : public GarbageCollected<CounterStyle> {
   // Additive weights, for the 'additive' system only.
   Vector<wtf_size_t> additive_weights_;
 
+  String negative_prefix_ = "-";
+  String negative_suffix_;
+
   friend class CounterStyleMapTest;
 };
 

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

@@ -176,4 +176,34 @@ TEST_F(CounterStyleTest, CyclicFallback) {
   EXPECT_EQ("6", foo.GenerateRepresentation(6));
 }
 
+TEST_F(CounterStyleTest, CustomNegative) {
+  InsertStyleElement(R"CSS(
+    @counter-style financial-decimal {
+      system: extends decimal;
+      negative: '(' ')';
+    }
+
+    @counter-style extended {
+      system: extends financial-decimal;
+    }
+  )CSS");
+  UpdateAllLifecyclePhasesForTest();
+
+  // Getting custom 'negative' directly from descriptor value.
+  const CounterStyle& financial_decimal = GetCounterStyle("financial-decimal");
+  EXPECT_EQ("(999)", financial_decimal.GenerateRepresentation(-999));
+  EXPECT_EQ("(1)", financial_decimal.GenerateRepresentation(-1));
+  EXPECT_EQ("0", financial_decimal.GenerateRepresentation(0));
+  EXPECT_EQ("1", financial_decimal.GenerateRepresentation(1));
+  EXPECT_EQ("99", financial_decimal.GenerateRepresentation(99));
+
+  // Getting custom 'negative' indirectly by extending a counter style.
+  const CounterStyle& extended = GetCounterStyle("extended");
+  EXPECT_EQ("(999)", extended.GenerateRepresentation(-999));
+  EXPECT_EQ("(1)", extended.GenerateRepresentation(-1));
+  EXPECT_EQ("0", extended.GenerateRepresentation(0));
+  EXPECT_EQ("1", extended.GenerateRepresentation(1));
+  EXPECT_EQ("99", extended.GenerateRepresentation(99));
+}
+
 }  // namespace blink