Implemented class literals in the VM.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
===================================================================
--- runtime/vm/flow_graph_builder.cc	(revision 16515)
+++ runtime/vm/flow_graph_builder.cc	(working copy)
@@ -547,11 +547,19 @@
 }
 
 
-// Type nodes only occur as the right-hand side of instanceof comparisons,
-// and they are handled specially in that context.
-void EffectGraphVisitor::VisitTypeNode(TypeNode* node) { UNREACHABLE(); }
+// Type nodes are used when a type is referenced as a literal. Type nodes
+// can also be used for the right-hand side of instanceof comparisons,
+// but they are handled specially in that context, not here.
+void EffectGraphVisitor::VisitTypeNode(TypeNode* node) {
+  return;
+}
 
 
+void ValueGraphVisitor::VisitTypeNode(TypeNode* node) {
+  ReturnDefinition(new ConstantInstr(node->type()));
+}
+
+
 // Returns true if the type check can be skipped, for example, if the
 // destination type is dynamic or if the compile type of the value is a subtype
 // of the destination type.