Change the default Dart-to-JavaScript compiler in the editor to be dart2js.

editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/frog/FrogCompiler.java

 /*
  * Copyright 2012 Dart project authors.
  * 
  * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
  * in compliance with the License. You may obtain a copy of the License at
  * 
  * http://www.eclipse.org/legal/epl-v10.html
  * 
  * Unless required by applicable law or agreed to in writing, software distributed under the License
  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
@@ skipping 99 matching lines @@
     FrogCompiler compiler;
 
     final CountDownLatch latch;
 
     if (DartCoreDebug.ENABLE_DOUBLE_COMPILATION) {
       latch = new CountDownLatch(1);
     } else {
       latch = new CountDownLatch(0);
     }
 
-    compiler = new FrogCompiler();
+    compiler = new Dart2JSCompiler();
 
     console.clear();
     console.println("Generating JavaScript...");
 
     try {
       if (DartCoreDebug.ENABLE_DOUBLE_COMPILATION) {
         new Thread(new Runnable() {
           @Override
           public void run() {
             try {
-              runDart2JSCompile(inputPath, outputPath, console);
+              runFrogCompile(inputPath, outputPath, console);
             } finally {
               latch.countDown();
             }
           }
         }).start();
       }
 
       CompilationResult result = compiler.compile(inputPath, outputPath, monitor);
 
       refreshResources(library.getCorrespondingResource());
 
       displayCompilationResult(compiler, result, outputPath, startTime, console);
 
       try {
         latch.await();
       } catch (InterruptedException ex) {
 
       }
 
       return result;
     } catch (IOException ioe) {
       throw new CoreException(new Status(IStatus.ERROR, DartCore.PLUGIN_ID, ioe.toString(), ioe));
     }
   }
 
-  protected static void runDart2JSCompile(IPath inputPath, IPath outputPath, MessageConsole console) {
+  protected static void runFrogCompile(IPath inputPath, IPath outputPath, MessageConsole console) {
     long startTime = System.currentTimeMillis();
 
     String outName = outputPath.lastSegment() + "_";
 
     outputPath = outputPath.removeLastSegments(1).append(outName);
 
-    FrogCompiler compiler = new Dart2JSCompiler();
+    FrogCompiler compiler = new FrogCompiler();
 
     try {
       CompilationResult result = compiler.compile(inputPath, outputPath, new NullProgressMonitor());
 
       displayCompilationResult(compiler, result, outputPath, startTime, console);
     } catch (IOException ioe) {
       DartCore.logError(ioe);
     }
   }
 
@@ skipping 111 matching lines @@
     if (packageRoot != null) {
       args.add("--package-root=" + packageRoot);
     }
     args.add("--out=" + outputPath.toOSString());
     args.add(inputPath.toOSString());
 
     return args;
   }
 
 }