Issue 1548. If URI can not be parsed, return null.

compiler/java/com/google/dart/runner/BundleLibrarySource.java

 // Copyright (c) 2011, 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.
 
 package com.google.dart.runner;
 
 import com.google.dart.compiler.DartSource;
 import com.google.dart.compiler.LibrarySource;
 import com.google.dart.compiler.UrlDartSource;
 import com.google.dart.compiler.UrlSource;
@@ skipping 20 matching lines @@
 
   public BundleLibrarySource(ClassLoader loader, String basePath, String filename)
       throws URISyntaxException {
     super(loader.getResource(basePath + filename).toURI());
     this.loader = loader;
     this.basePath = basePath;
     this.filename = filename;
   }
 
   @Override
-  public LibrarySource getImportFor(String filename) {
+  public LibrarySource getImportFor(String relPath) {
     try {
-      return new BundleLibrarySource(loader, basePath, filename);
+      return new BundleLibrarySource(loader, basePath, relPath);
     } catch (URISyntaxException e) {
-      throw new AssertionError();
+      return null;
     }
   }
 
   @Override
-  public DartSource getSourceFor(final String relPath) {
+  public DartSource getSourceFor(String relPath) {
     try {
       return new BundleDartSource(loader, basePath, relPath);
     } catch (URISyntaxException e) {
-      throw new AssertionError(e);
+      return null;
     }
   }
 
   @Override
   public String getName() {
     return basePath + filename;
   }
 }