Add a command line option to use the new CPS based backend.

pkg/compiler/lib/src/dart2js.dart

 // Copyright (c) 2013, 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.
 
 library dart2js.cmdline;
 
 import 'dart:async'
     show Future, EventSink;
 import 'dart:convert' show UTF8, LineSplitter;
 import 'dart:io'
@@ skipping 284 matching lines @@
     new OptionHandler('--suppress-warnings', (_) {
       diagnosticHandler.showWarnings = false;
       passThrough('--suppress-warnings');
     }),
     new OptionHandler('--fatal-warnings', passThrough),
     new OptionHandler('--suppress-hints',
                       (_) => diagnosticHandler.showHints = false),
     new OptionHandler(
         '--output-type=dart|--output-type=dart-multi|--output-type=js',
         setOutputType),
+    new OptionHandler('--use-cps-ir', passThrough),
     new OptionHandler('--verbose', setVerbose),
     new OptionHandler('--version', (_) => wantVersion = true),
     new OptionHandler('--library-root=.+', setLibraryRoot),
     new OptionHandler('--out=.+|-o.*', setOutput, multipleArguments: true),
     new OptionHandler('--allow-mock-compilation', passThrough),
     new OptionHandler('--minify|-m', implyCompilation),
     new OptionHandler('--preserve-uris', passThrough),
     new OptionHandler('--force-strip=.*', setStrip),
     new OptionHandler('--disable-diagnostic-colors',
                       (_) => diagnosticHandler.enableColors = false),
@@ skipping 308 matching lines @@
   --dump-info
     Generates an out.info.json file with information about the generated code.
     You can inspect the generated file with the viewer at:
         https://dart-lang.github.io/dump-info-visualizer/
     This feature is currently not supported in combination with the 
     '--output-type=dart' option.
 
   --generate-code-with-compile-time-errors
     Generates output even if the program contains compile-time errors. Use the
     exit code to determine if compilation failed.
+
+  --use-cps-ir
+    Experimental.  Use the new CPS based backend for code generation.
 '''.trim());
 }
 
 void helpAndExit(bool wantHelp, bool wantVersion, bool verbose) {
   if (wantVersion) {
     var version = (BUILD_ID == null)
         ? '<non-SDK build>'
         : BUILD_ID;
     print('Dart-to-JavaScript compiler (dart2js) version: $version');
   }
@@ skipping 94 matching lines @@
       } else if (exitCode == 253) {
         print(">>> TEST CRASH");
       } else {
         print(">>> TEST FAIL");
       }
       stderr.writeln(">>> EOF STDERR");
       subscription.resume();
     });
   });
 }