Hook up the --minify option in dart2js and use it to get rid of unnecessary whitespace inside funct…

lib/compiler/implementation/js/printer.dart

 // Copyright (c) 2012, 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.
 
 class Printer implements NodeVisitor {
-  final bool shouldCompressOutput = false;
+  final bool shouldCompressOutput;
   leg.Compiler compiler;
   var positionElement;
   leg.CodeBuffer outBuffer;
   int indentLevel = 0;
   bool inForInit = false;
   bool atStatementBegin = false;
   final DanglingElseVisitor danglingElseVisitor;
 
   Printer(leg.Compiler compiler, this.positionElement)
-      : this.compiler = compiler,
+      : shouldCompressOutput = compiler.enableMinification,
+        this.compiler = compiler,
         outBuffer = new leg.CodeBuffer(),
         danglingElseVisitor = new DanglingElseVisitor(compiler);
 
   void spaceOut() {
     if (!shouldCompressOutput) out(" ");
   }
   void lineOut() {
     if (!shouldCompressOutput) out("\n");
   }
 
@@ skipping 790 matching lines @@
 }
 
 
 leg.CodeBuffer prettyPrint(Node node,
                            leg.Compiler compiler,
                            Dynamic positionElement) {
   Printer printer = new Printer(compiler, positionElement);
   printer.visit(node);
   return printer.outBuffer;
 }