Enabled class name minification in production mode.

compiler/java/com/google/dart/compiler/DefaultCompilerConfiguration.java

Index: compiler/java/com/google/dart/compiler/DefaultCompilerConfiguration.java
===================================================================
--- compiler/java/com/google/dart/compiler/DefaultCompilerConfiguration.java	(revision 369)
+++ compiler/java/com/google/dart/compiler/DefaultCompilerConfiguration.java	(working copy)
@@ -51,7 +51,9 @@
       return new DartIsolateStubGenerator(compilerOptions.getIsolateStubClasses(),
                                           compilerOptions.getIsolateStubOutputFile());
     } else if (compilerOptions.shouldOptimize()) {
-      return new ClosureJsBackend(compilerOptions.generateHumanReadableOutput());
+      return new ClosureJsBackend(
+          compilerOptions.developerModeChecks(),
+          compilerOptions.generateHumanReadableOutput());
     } else {
       return new JavascriptBackend();
     }