Remove dead code _resolveUri in builtin.dart is not used anymore.

runtime/bin/builtin.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights solveserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library builtin;
 // NOTE: Do not import 'dart:io' in builtin.
 import 'dart:async';
 import 'dart:collection';
 import 'dart:_internal';
 import 'dart:isolate';
@@ skipping 243 matching lines @@
   // Remember the root script URI so that we can resolve packages based on
   // this location.
   _rootScript = scriptUri;
 
   if (_traceLoading) {
     _log('Resolved entry point to: $_rootScript');
   }
   return scriptUri.toString();
 }
 
-// Embedder Entrypoint:
-// Function called by standalone embedder to resolve uris when the VM requests
-// Dart_kCanonicalizeUrl from the tag handler.
-String _resolveUri(String base, String userString) {
-  if (!_setupCompleted) {
-    _setupHooks();
-  }
-
-  if (_traceLoading) {
-    _log('Resolving: $userString from $base');
-  }
-
-  var baseUri = Uri.parse(base);
-  var result = baseUri.resolve(userString).toString();
-  if (_traceLoading) {
-    _log('Resolved $userString in $base to $result');
-  }
-
-  return result;
-}
-
 // Embedder Entrypoint (gen_snapshot):
 // Resolve relative paths relative to working directory.
 String _resolveInWorkingDirectory(String fileName) {
   if (!_setupCompleted) {
     _setupHooks();
   }
   if (_workingDirectory == null) {
     throw 'No current working directory set.';
   }
   var name = _sanitizeWindowsPath(fileName);
@@ skipping 112 matching lines @@
     if (_traceLoading) {
       _log("Exception when resolving package URI: $packageUri");
     }
     result = null;
   }
   if (_traceLoading) {
     _log("Resolved '$packageUri' to '$result'");
   }
   return result;
 }