Support symbol literals.

sdk/lib/_internal/compiler/implementation/ssa/builder.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
index 12be2f687abdea5f1bd82487b3ae575be137cba5..352f1a014b7e159fbd5e80ba5ca0e0cf0dd7bfcc 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
@@ -4055,6 +4055,14 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
   void visitLiteralString(LiteralString node) {
     stack.add(graph.addConstantString(node.dartString, node, compiler));
   }
+  
+  void visitSymbolLiteral(SymbolLiteral node) {
+    ConstantHandler handler = compiler.constantHandler;
+    ConstructedConstant constant = 
+        handler.compileNodeWithDefinitions(node, elements);
+    stack.add(graph.addConstant(constant, compiler));
+    compiler.enqueuer.codegen.registerConstSymbol(node.nameString, elements);
+  }
 
   void visitStringJuxtaposition(StringJuxtaposition node) {
     if (!node.isInterpolation) {