Ensure apidoc exits with non-zero exit code when dart2js crashes.

dart/utils/apidoc/apidoc.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.
 
 /**
  * This generates the reference documentation for the core libraries that come
  * with dart. It is built on top of dartdoc, which is a general-purpose library
  * for generating docs from any Dart code. This library extends that to include
  * additional information and styling specific to our standard library.
  *
@@ skipping 132 matching lines @@
         scriptDir.append('../../sdk/lib/_internal/dartdoc/');
     // Select the libraries to include in the produced documentation:
     apidoc.includeApi = true;
     apidoc.includedLibraries = includedLibraries;
 
     // TODO(amouravski): make apidoc use roughly the same flow as bin/dartdoc.
     Future.wait([copiedStatic, copiedApiDocStatic, htmlDiff])
       .then((_) => apidoc.documentLibraries(apidocLibraries, libPath, pkgPath))
       .then((_) => compileScript(mode, outputDir, libPath))
       .then((_) => print(apidoc.status))
-      .catchError((e) => print('Error: generation failed: ${e.error}'))
+      .catchError((e) {
+        print('Error: generation failed: ${e}');
+        apidoc.cleanup();
+        exit(1);
+      })
       .whenComplete(() => apidoc.cleanup());
   });
 }
 
 class Apidoc extends Dartdoc {
   /** Big ball of JSON containing the scraped MDN documentation. */
   final Map mdn;
 
 
   // A set of type names (TypeMirror.simpleName values) to ignore while
@@ skipping 271 matching lines @@
     final typeName = member.owner.simpleName;
     var memberName = '$typeName.${member.simpleName}';
     if (member is MethodMirror && (member.isConstructor || member.isFactory)) {
       final separator = member.constructorName == '' ? '' : '.';
       memberName = 'new $typeName$separator${member.constructorName}';
     }
 
     return a(memberUrl(member), memberName);
   }
 }