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 5e34fcd429b455817fa53ed143fba77260baa309..3da3d209abb718ab71f8e9cd17f08d6d3e204da2 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
@@ -4074,6 +4074,14 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
     stack.add(graph.addConstantString(node.dartString, node, compiler));
   }
 
+  void visitLiteralSymbol(LiteralSymbol 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) {
       // This is a simple string with no interpolations.