Fixes #254 - Better stacktrace support

lib/src/codegen/js_codegen.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 dev_compiler.src.codegen.js_codegen;
 
 import 'dart:collection' show HashSet, HashMap, SplayTreeSet;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/src/generated/ast.dart' hide ConstantEvaluator;
@@ skipping 2304 matching lines @@
       notNull(node.condition),
       _visit(node.thenExpression),
       _visit(node.elseExpression)
     ]);
   }
 
   @override
   visitThrowExpression(ThrowExpression node) {
     var expr = _visit(node.expression);
     if (node.parent is ExpressionStatement) {
-      return js.statement('throw #;', expr);
+      return js.statement('dart.throw(#);', expr);
     } else {
-      return js.call('dart.throw_(#)', expr);
+      return js.call('dart.throw(#)', expr);
     }
   }
 
   @override
   visitRethrowExpression(RethrowExpression node) {
     if (node.parent is ExpressionStatement) {
       return js.statement('throw #;', _visit(_catchParameter));
     } else {
-      return js.call('dart.throw_(#)', _visit(_catchParameter));
+      return js.call('throw #', _visit(_catchParameter));
     }
   }
 
   @override
   JS.If visitIfStatement(IfStatement node) {
     return new JS.If(notNull(node.condition), _visit(node.thenStatement),
         _visit(node.elseStatement));
   }
 
   @override
@@ skipping 245 matching lines @@
       _visit(node.expression);
 
   @override
   visitBooleanLiteral(BooleanLiteral node) => js.boolean(node.value);
 
   @override
   JS.Expression visitExpression(Expression node) =>
       _unimplementedCall('Unimplemented ${node.runtimeType}: $node');
 
   JS.Expression _unimplementedCall(String comment) {
-    return js.call('dart.throw_(#)', [js.escapedString(comment)]);
+    return js.call('dart.throw(#)', [js.escapedString(comment)]);
   }
 
   @override
   visitNode(AstNode node) {
     // TODO(jmesserly): verify this is unreachable.
     throw 'Unimplemented ${node.runtimeType}: $node';
   }
 
   _visit(AstNode node) {
     if (node == null) return null;
@@ skipping 210 matching lines @@
 
 class _JsThisFinder extends JS.BaseVisitor {
   bool found = false;
   visitThis(JS.This node) {
     found = true;
   }
   visitNode(JS.Node node) {
     if (!found) super.visitNode(node);
   }
 }