Add option --generate-code-with-compile-time-errors.

dart/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 325 matching lines @@
     new OptionHandler('--deferred-map=.+', implyCompilation),
     new OptionHandler('--dump-info', implyCompilation),
     new OptionHandler('--disallow-unsafe-eval',
                       (_) => hasDisallowUnsafeEval = true),
     new OptionHandler('--show-package-warnings', passThrough),
     new OptionHandler('--csp', passThrough),
     new OptionHandler('--enable-experimental-mirrors', passThrough),
     new OptionHandler('--enable-async', setEnableAsync),
     new OptionHandler('--enable-enum', passThrough),
     new OptionHandler('--allow-native-extensions', setAllowNativeExtensions),
+    new OptionHandler('--generate-code-with-compile-time-errors', passThrough),
+
+    // The following three options must come last.
     new OptionHandler('-D.+=.*', addInEnvironment),
-
-    // The following two options must come last.
     new OptionHandler('-.*', (String argument) {
       helpAndFail("Unknown option '$argument'.");
     }),
     new OptionHandler('.*', (String argument) {
       arguments.add(nativeToUriPath(argument));
     })
   ];
 
   parseCommandLine(handlers, argv);
   if (wantHelp || wantVersion) {
@@ skipping 243 matching lines @@
 
   --deferred-map=<file>
     Generates a json file with a mapping from each deferred import to a list of
     the part.js files that will be loaded.
 
   --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/
 
+  --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.
 '''.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 91 matching lines @@
       } else if (exitCode == 253) {
         print(">>> TEST CRASH");
       } else {
         print(">>> TEST FAIL");
       }
       stderr.writeln(">>> EOF STDERR");
       subscription.resume();
     });
   });
 }