Remove frog dependencies from lib/compiler.

lib/compiler/implementation/dart2js.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('dart2js');
 
 #import('dart:io');
+#import('dart:uri');
 #import('dart:utf');
 
-#import('../../uri/uri.dart');
 #import('../compiler.dart', prefix: 'api');
 #import('colors.dart');
 #import('source_file.dart');
 
 String relativize(Uri base, Uri uri) {
   if (base.scheme == 'file' &&
       base.scheme == uri.scheme &&
       base.userInfo == uri.userInfo &&
       base.domain == uri.domain &&
       base.port == uri.port &&
@@ skipping 128 matching lines @@
   var bytes = file.readListSync(buffer, 0, length);
   file.closeSync();
   return new String.fromCharCodes(new Utf8Decoder(buffer).decodeRest());
 }
 
 String getCurrentDirectory() {
   String dir = new File(".").fullPathSync();
   if (dir.endsWith("/")) return dir;
   return "$dir/";
 }