'>>>' and '/deep/' no longer share a token

This allows csslib to preserve the original combinator choice when printing an
AST.

Author: leonsenft

lib/parser.dart

@@ -1248,7 +1248,7 @@ class _Parser {
         _eat(TokenKind.GREATER);
         if (_maybeEat(TokenKind.GREATER)) {
           _eat(TokenKind.GREATER);
-          combinatorType = TokenKind.COMBINATOR_DEEP;
+          combinatorType = TokenKind.COMBINATOR_SHADOW_PIERCING_DESCENDANT;
         } else {
           combinatorType = TokenKind.COMBINATOR_GREATER;
         }

lib/src/tokenkind.dart

@@ -100,9 +100,10 @@ class TokenKind {
   static const int COMBINATOR_PLUS = 515; // + combinator
   static const int COMBINATOR_GREATER = 516; // > combinator
   static const int COMBINATOR_TILDE = 517; // ~ combinator
-  static const int COMBINATOR_DEEP = 518; // /deep/ or >>> combinator
+  static const int COMBINATOR_SHADOW_PIERCING_DESCENDANT = 518; // >>>
+  static const int COMBINATOR_DEEP = 519; // /deep/ (aliases >>>)
 
-  static const int UNARY_OP_NONE = 519; // No unary operator present.
+  static const int UNARY_OP_NONE = 520; // No unary operator present.
 
   // Attribute match types:
   static const int INCLUDES = 530; // '~='

lib/src/tree.dart

@@ -121,11 +121,15 @@ class SimpleSelectorSequence extends TreeNode {
   bool get isCombinatorDescendant =>
       combinator == TokenKind.COMBINATOR_DESCENDANT;
   bool get isCombinatorDeep => combinator == TokenKind.COMBINATOR_DEEP;
+  bool get isCombinatorShadowPiercingDescendant =>
+      combinator == TokenKind.COMBINATOR_SHADOW_PIERCING_DESCENDANT;
 
   String get _combinatorToString {
     switch (combinator) {
-      case TokenKind.COMBINATOR_DEEP:
+      case TokenKind.COMBINATOR_SHADOW_PIERCING_DESCENDANT:
         return ' >>> ';
+      case TokenKind.COMBINATOR_DEEP:
+        return ' /deep/ ';
       case TokenKind.COMBINATOR_DESCENDANT:
         return ' ';
       case TokenKind.COMBINATOR_GREATER:

lib/src/tree_printer.dart

@@ -271,8 +271,10 @@ class _TreePrinter extends Visitor {
       output.writeValue('combinator', ">");
     } else if (node.isCombinatorTilde) {
       output.writeValue('combinator', "~");
-    } else if (node.isCombinatorDeep) {
+    } else if (node.isCombinatorShadowPiercingDescendant) {
       output.writeValue('combinator', '>>>');
+    } else if (node.isCombinatorDeep) {
+      output.writeValue('combinator', '/deep/');
     } else {
       output.writeValue('combinator', "ERROR UNKNOWN");
     }

test/selector_test.dart

@@ -61,7 +61,7 @@ void testSelectorSuccesses() {
 
   selectorAst = selector('.a /deep/ .b', errors: errors..clear());
   expect(errors.isEmpty, true, reason: errors.toString());
-  expect(compactOuptut(selectorAst), '.a >>> .b');
+  expect(compactOuptut(selectorAst), '.a /deep/ .b');
 
   selectorAst = selector('.x >>> .y', errors: errors..clear());
   expect(errors.isEmpty, true, reason: errors.toString());