Rename classes, methods and fields when minifying

sdk/lib/_internal/compiler/implementation/js_backend/backend.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.
 
 part of js_backend;
 
 typedef void Recompile(Element element);
 
 class ReturnInfo {
   HType returnType;
@@ skipping 654 matching lines @@
   final List<Element> invalidateAfterCodegen;
   ArgumentTypesRegistry argumentTypes;
   FieldTypesRegistry fieldTypes;
 
   final Interceptors interceptors;
 
   List<CompilerTask> get tasks {
     return <CompilerTask>[builder, optimizer, generator, emitter];
   }
 
-  JavaScriptBackend(Compiler compiler,
-                    bool generateSourceMap,
-                    bool disableEval)
-      : namer = new Namer(compiler),
+  JavaScriptBackend(Compiler compiler, bool generateSourceMap, bool disableEval)
+      : namer = determineNamer(compiler),
         returnInfo = new Map<Element, ReturnInfo>(),
         invalidateAfterCodegen = new List<Element>(),
         interceptors = new Interceptors(compiler),
         super(compiler, JAVA_SCRIPT_CONSTANT_SYSTEM) {
     emitter = disableEval
         ? new CodeEmitterNoEvalTask(compiler, namer, generateSourceMap)
         : new CodeEmitterTask(compiler, namer, generateSourceMap);
     builder = new SsaBuilderTask(this);
     optimizer = new SsaOptimizerTask(this);
     generator = new SsaCodeGeneratorTask(this);
     argumentTypes = new ArgumentTypesRegistry(this);
     fieldTypes = new FieldTypesRegistry(this);
   }
 
+  static Namer determineNamer(Compiler compiler) {
+    return compiler.enableMinification ?
+        new MinifyNamer(compiler) :
+        new Namer(compiler);
+  }
+
   Element get cyclicThrowHelper {
     return compiler.findHelper(const SourceString("throwCyclicInit"));
   }
 
   JavaScriptItemCompilationContext createItemCompilationContext() {
     return new JavaScriptItemCompilationContext();
   }
 
   Element getInterceptor(Selector selector) {
     return interceptors.getStaticInterceptor(selector);
@@ skipping 249 matching lines @@
     print("Inferred return types:");
     print("----------------------");
     dumpReturnTypes();
     print("");
     print("Inferred field types:");
     print("------------------------");
     fieldTypes.dump();
     print("");
   }
 }