dart2js: Add --fast-startup flag.

pkg/compiler/lib/src/compiler.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 dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 1038 matching lines @@
             this.useCpsIr: false,
             this.useFrequencyNamer: false,
             this.verbose: false,
             this.sourceMapUri: null,
             this.outputUri: null,
             this.buildId: UNDETERMINED_BUILD_ID,
             this.terseDiagnostics: false,
             this.deferredMapUri: null,
             this.dumpInfo: false,
             this.showPackageWarnings: false,
+            bool useStartupEmitter: false,
             this.useContentSecurityPolicy: false,
             this.suppressWarnings: false,
             this.fatalWarnings: false,
             bool hasIncrementalSupport: false,
             this.enableExperimentalMirrors: false,
             this.allowNativeExtensions: false,
             this.generateCodeWithCompileTimeErrors: false,
             this.testMode: false,
             api.CompilerOutput outputProvider,
             List<String> strips: const []})
@@ skipping 24 matching lines @@
     }
 
     // TODO(johnniwinther): Separate the dependency tracking from the enqueuing
     // for global dependencies.
     globalDependencies =
         new CodegenRegistry(this, new TreeElementMapping(null));
 
     if (emitJavaScript) {
       js_backend.JavaScriptBackend jsBackend =
           new js_backend.JavaScriptBackend(
-              this, generateSourceMap: generateSourceMap);
+              this, generateSourceMap: generateSourceMap,
+              useStartupEmitter: useStartupEmitter);
       backend = jsBackend;
     } else {
       backend = new dart_backend.DartBackend(this, strips,
                                              multiFile: dart2dartMultiFile);
       if (dumpInfo) {
         throw new ArgumentError('--dump-info is not supported for dart2dart.');
       }
     }
 
     tasks = [
@@ skipping 1396 matching lines @@
   InterfaceType streamType([DartType elementType]) {
     InterfaceType type = streamClass.computeType(compiler);
     if (elementType == null) {
       return streamClass.rawType;
     }
     return type.createInstantiation([elementType]);
   }
 }
 
 typedef void InternalErrorFunction(Spannable location, String message);