Use '--source-map' and '--out' options to support source maps from non-commandline.

sdk/lib/_internal/compiler/implementation/apiimpl.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.
 
 library leg_apiimpl;
 
 import 'dart:async';
 
 import '../compiler.dart' as api;
 import 'dart2jslib.dart' as leg;
@@ skipping 39 matching lines @@
             analyzeOnly: hasOption(options, '--analyze-only'),
             analyzeSignaturesOnly:
                 hasOption(options, '--analyze-signatures-only'),
             strips: extractCsvOption(options, '--force-strip='),
             enableConcreteTypeInference:
                 hasOption(options, '--enable-concrete-type-inference'),
             disableTypeInferenceFlag:
                 hasOption(options, '--disable-type-inference'),
             preserveComments: hasOption(options, '--preserve-comments'),
             verbose: hasOption(options, '--verbose'),
-            sourceMapUri: extractSourceMapUri(options),
+            sourceMapUri: extractUriOption(options, '--source-map='),
+            outputUri: extractUriOption(options, '--out='),
             terseDiagnostics: hasOption(options, '--terse'),
             dumpInfo: hasOption(options, '--dump-info'),
             buildId: extractStringOption(
                 options, '--build-id=',
                 "build number could not be determined"),
             showPackageWarnings:
                 hasOption(options, '--show-package-warnings')) {
     if (!libraryRoot.path.endsWith("/")) {
       throw new ArgumentError("libraryRoot must end with a /");
     }
     if (packageRoot != null && !packageRoot.path.endsWith("/")) {
       throw new ArgumentError("packageRoot must end with a /");
     }
   }
 
   static String extractStringOption(List<String> options,
                                     String prefix,
                                     String defaultValue) {
     for (String option in options) {
       if (option.startsWith(prefix)) {
         return option.substring(prefix.length);
       }
     }
     return defaultValue;
   }
 
-  static Uri extractSourceMapUri(List<String> options) {
-    var option = extractStringOption(options, '--source-map=', null);
+  static Uri extractUriOption(List<String> options, String prefix) {
+    var option = extractStringOption(options, prefix, null);
     return (option == null) ? null : Uri.parse(option);
   }
 
   // CSV: Comma separated values.
   static List<String> extractCsvOption(List<String> options, String prefix) {
     for (String option in options) {
       if (option.startsWith(prefix)) {
         return option.substring(prefix.length).split(',');
       }
     }
@@ skipping 232 matching lines @@
   }
 
   void diagnoseCrashInUserCode(String message, exception, stackTrace) {
     hasCrashed = true;
     print('$message: ${tryToString(exception)}');
     print(tryToString(stackTrace));
   }
 
   fromEnvironment(String name) => environment[name];
 }