Reapply r27285: "Support dynamic as type literal."

sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart_backend;
 
 class LocalPlaceholder {
   final String identifier;
   final Set<Node> nodes;
   LocalPlaceholder(this.identifier) : nodes = new Set<Node>();
@@ skipping 296 matching lines @@
   }
 
   void makeElementPlaceholder(Node node, Element element) {
     assert(element != null);
     if (identical(element, entryFunction)) return;
     if (identical(element.getLibrary(), coreLibrary)) return;
     if (element.getLibrary().isPlatformLibrary && !element.isTopLevel()) {
       return;
     }
     if (element == compiler.dynamicClass) {
-      internalError(
-          'Should never make element placeholder for dynamic type element',
-          node: node);
+      return;
     }
     elementNodes.putIfAbsent(element, () => new Set<Node>()).add(node);
   }
 
   void makePrivateIdentifier(Identifier node) {
     assert(node != null);
     privateNodes.putIfAbsent(
         currentElement.getLibrary(), () => new Set<Identifier>()).add(node);
   }
 
@@ skipping 294 matching lines @@
 
   visitBlock(Block node) {
     for (Node statement in node.statements.nodes) {
       if (statement is VariableDefinitions) {
         makeVarDeclarationTypePlaceholder(statement);
       }
     }
     node.visitChildren(this);
   }
 }