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

http://code.google.com/p/dart/issues/detail?id=1548

This is also specified in JavaDoc for this method.

R=danrubel@google.com
BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com//9420011

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@4341 260f80e4-7a28-3924-810f-c04153c831b5

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

@@ -38,20 +38,20 @@ class BundleLibrarySource extends UrlSource implements LibrarySource {
   }
 
   @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;
     }
   }