Enabled class name minification in production mode.

compiler/java/com/google/dart/runner/DartRunner.java

 // Copyright (c) 2011, 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.
 
 package com.google.dart.runner;
 
 import com.google.common.base.Joiner;
 import com.google.common.collect.Lists;
 import com.google.common.io.CharStreams;
 import com.google.common.io.Files;
@@ skipping 319 matching lines @@
     public CompilationResult(String js, SourceMapping mapping) {
       this.mapping = mapping;
       this.js = js;
     }
   }
 
   private static CompilationResult compileApp (LibrarySource app, List<LibrarySource> imports,
       final DartRunnerOptions options, DartCompilerListener listener) throws RunnerError {
     Backend backend;
     if (options.shouldOptimize()) {
-      backend = new ClosureJsBackend(options.generateHumanReadableOutput());
+      backend = new ClosureJsBackend(
+          options.developerModeChecks(),
+          options.generateHumanReadableOutput());
     } else {
       backend = new JavascriptBackend();
     }
     CompilerConfiguration config = new DefaultCompilerConfiguration(backend, options) {
       @Override
       public boolean expectEntryPoint() {
         return true;
       }
 
       @Override
@@ skipping 45 matching lines @@
       Reader r = provider.getArtifactReader(app, "", backend.getAppExtension());
       String js = CharStreams.toString(r);
       r.close();
       return new CompilationResult(js, mapping);
     } catch (IOException e) {
       // This can't happen; it's just a StringWriter.
       throw new AssertionError(e);
     }
   }
 }