Accept more labels per switch case.

lib/compiler/implementation/scanner/listener.dart

Index: lib/compiler/implementation/scanner/listener.dart
diff --git a/lib/compiler/implementation/scanner/listener.dart b/lib/compiler/implementation/scanner/listener.dart
index 74dd30f0dc1b51b65e5489840bdb8bc7bd995db5..3744f66de2bde5bf244db819f96823fe6270403b 100644
--- a/lib/compiler/implementation/scanner/listener.dart
+++ b/lib/compiler/implementation/scanner/listener.dart
@@ -251,6 +251,9 @@ class Listener {
   void beginTryStatement(Token token) {
   }
 
+  void handleCaseMatch(Token caseKeyword, Token colon) {
+  }
+
   void handleCatchBlock(Token catchKeyword) {
   }
 
@@ -404,7 +407,7 @@ class Listener {
   void handleSuperExpression(Token token) {
   }
 
-  void handleSwitchCase(Token labelToken, int expressionCount,
+  void handleSwitchCase(int labelCount, int expressionCount,
                         Token defaultKeyword, int statementCount,
                         Token firstToken, Token endToken) {
   }
@@ -1331,6 +1334,10 @@ class NodeListener extends ElementListener {
                               tryKeyword, finallyKeyword));
   }
 
+  void handleCaseMatch(Token caseKeyword, Token colon) {
+    pushNode(new CaseMatch(caseKeyword, popNode(), colon));
+  }
+
   void handleCatchBlock(Token catchKeyword) {
     Block block = popNode();
     NodeList formals = popNode();
@@ -1353,16 +1360,29 @@ class NodeListener extends ElementListener {
     pushNode(new NodeList(beginToken, caseNodes, endToken, null));
   }
 
-  void handleSwitchCase(Token labelToken, int expressionCount,
+  void handleSwitchCase(int labelCount, int caseCount,
                         Token defaultKeyword, int statementCount,
                         Token firstToken, Token endToken) {
     NodeList statements = makeNodeList(statementCount, null, null, null);
-    NodeList expressions = makeNodeList(expressionCount, null, null, null);
-    Label label = null;
-    if (labelToken !== null) {
-      label = popNode();
+    Link<Label> labels = const EmptyLink<Label>();
+    Link<CaseMatch> cases = const EmptyLink<CaseMatch>();
+    while (labelCount > 0 || caseCount > 0) {
+      Node node = popNode();
+      Label label = node.asLabel();
+      if (label !== null) {
+        labels = labels.prepend(label);
+        labelCount--;
+      } else {
+        CaseMatch match = node.asCaseMatch();
+        assert(match !== null);
+        cases = cases.prepend(match);
+        caseCount--;
+      }
     }
-    pushNode(new SwitchCase(label, expressions, defaultKeyword, statements,
+
+    NodeList caseList = new NodeList(null, cases, null, null);
+    NodeList labelList = new NodeList(null, labels, null, null);
+    pushNode(new SwitchCase(labelList, caseList, defaultKeyword, statements,
                             firstToken));
   }