Redo "Steps towards making dart2js JS AST templates an indepentent library."

pkg/compiler/lib/src/js/rewrite_async.dart

 // Copyright (c) 2015, 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.
 
 library rewrite_async;
 
 // TODO(sigurdm): Throws in catch-handlers are handled wrong.
 // TODO(sigurdm): Avoid using variables in templates. It could blow up memory
 // use.
 
@@ skipping 948 matching lines @@
       }, store: false);
       beginLabel(joinLabel);
       return new js.VariableUse(resultName);
     }
 
     return withExpression2(node.left, node.right,
         (left, right) => new js.Binary(node.op, left, right));
   }
 
   @override
-  js.Expression visitBlob(js.Blob node) {
-    return node;
-  }
-
-  @override
   void visitBlock(js.Block node) {
     for (js.Statement statement in node.statements) {
       visitStatement(statement);
     }
   }
 
   @override
   void visitBreak(js.Break node) {
     js.Node target = analysis.targets[node];
     if (!shouldTransform(target)) {
@@ skipping 831 matching lines @@
   }
 
   @override
   bool visitBinary(js.Binary node) {
     bool left = visit(node.left);
     bool right = visit(node.right);
     return left || right;
   }
 
   @override
-  bool visitBlob(js.Blob node) {
-    return false;
-  }
-
-  @override
   bool visitBlock(js.Block node) {
     bool containsAwait = false;
     for (js.Statement statement in node.statements) {
       if (visit(statement)) containsAwait = true;
     }
     return containsAwait;
   }
 
   @override
   bool visitBreak(js.Break node) {
@@ skipping 310 matching lines @@
     loopsAndSwitches.removeLast();
     return condition || body;
   }
 
   @override
   bool visitDartYield(js.DartYield node) {
     visit(node.expression);
     return true;
   }
 }