Add interfaces for a new compiler API.

tests/compiler/dart2js/deferred_dont_inline_deferred_globals_test.dart

 // Copyright (c) 2014, 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.
 
 // Test that the additional runtime type support is output to the right
 // Files when using deferred loading.
 
+import 'package:async_helper/async_helper.dart';
+import 'package:compiler/src/dart2jslib.dart';
 import 'package:expect/expect.dart';
-import "package:async_helper/async_helper.dart";
-import 'memory_source_file_helper.dart';
-import "dart:async";
-
-import 'package:compiler/src/dart2jslib.dart'
-       as dart2js;
-
-class MemoryOutputSink extends EventSink<String> {
-  StringBuffer mem = new StringBuffer();
-  void add(String event) {
-    mem.write(event);
-  }
-  void addError(String event, [StackTrace stackTrace]) {
-    Expect.isTrue(false);
-  }
-  void close() {}
-}
+import 'memory_compiler.dart';
+import 'output_collector.dart';
 
 void main() {
-  Uri script = currentDirectory.resolveUri(Platform.script);
-  Uri libraryRoot = script.resolve('../../../sdk/');
-  Uri packageRoot = script.resolve('./packages/');
-
-  var provider = new MemorySourceFileProvider(MEMORY_SOURCE_FILES);
-  var handler = new FormattingDiagnosticHandler(provider);
-
-  Map<String, MemoryOutputSink> outputs = new Map<String, MemoryOutputSink>();
-
-  MemoryOutputSink outputSaver(name, extension) {
-    if (name == '') {
-      name = 'main';
-    }
-    return outputs.putIfAbsent("$name.$extension", () {
-      return new MemoryOutputSink();
-    });
-  }
-
-  Compiler compiler = new Compiler(provider.readStringFromUri,
-                                   outputSaver,
-                                   handler.diagnosticHandler,
-                                   libraryRoot,
-                                   packageRoot,
-                                   [],
-                                   {});
+  OutputCollector collector = new OutputCollector();
+  Compiler compiler = compilerFor(
+      MEMORY_SOURCE_FILES,
+      outputProvider: collector);
   asyncTest(() => compiler.run(Uri.parse('memory:main.dart')).then((_) {
     lookupLibrary(name) {
       return compiler.libraryLoader.lookupLibrary(Uri.parse(name));
     }
 
-    var main = compiler.mainApp.find(dart2js.Compiler.MAIN);
+    var main = compiler.mainApp.find(Compiler.MAIN);
     Expect.isNotNull(main, "Could not find 'main'");
     compiler.deferredLoadTask.onResolutionComplete(main);
 
     var outputUnitForElement = compiler.deferredLoadTask.outputUnitForElement;
 
     var lib1 = lookupLibrary("memory:lib1.dart");
     var foo1 = lib1.find("finalVar");
     var ou_lib1 = outputUnitForElement(foo1);
 
-    String mainOutput = outputs["main.js"].mem.toString();
-    String lib1Output = outputs["out_${ou_lib1.name}.part.js"].mem.toString();
+    String mainOutput = collector.getOutput("", "js");
+    String lib1Output = collector.getOutput("out_${ou_lib1.name}", "part.js");
     // Test that the deferred globals are not inlined into the main file.
     RegExp re1 = new RegExp(r"= .string1");
     RegExp re2 = new RegExp(r"= .string2");
     Expect.isTrue(re1.hasMatch(lib1Output));
     Expect.isTrue(re2.hasMatch(lib1Output));
     Expect.isFalse(re1.hasMatch(mainOutput));
     Expect.isFalse(re2.hasMatch(mainOutput));
   }));
 }
 
 // Make sure that deferred constants are not inlined into the main hunk.
 const Map MEMORY_SOURCE_FILES = const {"main.dart": """
 import "dart:async";
 
 import 'lib1.dart' deferred as lib1;
 
 void main() {
   lib1.loadLibrary().then((_) {
     print(lib1.finalVar);
     print(lib1.globalVar);
     lib1.globalVar = "foobar";
     print(lib1.globalVar);
   });
 }
 """, "lib1.dart": """
 import "main.dart" as main;
 final finalVar = "string1";
 var globalVar = "string2";
 """};