dart2js: add --preserve-uris flag.

sdk/lib/_internal/compiler/js_lib/js_mirrors.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 dart._js_mirrors;
 
 import 'shared/runtime_data.dart' as encoding;
 import 'shared/embedded_names.dart' show
     ALL_CLASSES,
     LAZIES,
@@ skipping 123 matching lines @@
     return librariesByName[n(libraryName)].single;
   }
 
   static Map<String, List<LibraryMirror>> computeLibrariesByName() {
     disableTreeShaking();
     var result = new Map<String, List<LibraryMirror>>();
     var jsLibraries = JS_EMBEDDED_GLOBAL('JSExtendableArray|Null', LIBRARIES);
     if (jsLibraries == null) return result;
     for (List data in jsLibraries) {
       String name = data[0];
-      Uri uri = Uri.parse(data[1]);
+      String uriString = data[1];
+      Uri uri;
+      // The Uri has been compiled out. Create a URI from the simple name.
+      if (uriString != "") {
+        uri = Uri.parse(uriString);
+      } else {
+        uri = new Uri(scheme: 'https',
+                      host: 'dartlang.org',
+                      path: 'dart2js-stripped-uri',
+                      queryParameters: { 'lib': name });
+      }
       List<String> classes = data[2];
       List<String> functions = data[3];
       var metadataFunction = data[4];
       var fields = data[5];
       bool isRoot = data[6];
       var globalObject = data[7];
       List metadata = (metadataFunction == null)
           ? const [] : JS('List', '#()', metadataFunction);
       var libraries = result.putIfAbsent(name, () => <LibraryMirror>[]);
       libraries.add(
@@ skipping 2803 matching lines @@
   // have a part (following a '.') that starts with '_'.
   const int UNDERSCORE = 0x5f;
   if (name.isEmpty) return true;
   int index = -1;
   do {
     if (name.codeUnitAt(index + 1) == UNDERSCORE) return false;
     index = name.indexOf('.', index + 1);
   } while (index >= 0 && index + 1 < name.length);
   return true;
 }