Make EqualsIgnoringPrivateKey work with mixin applications.

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/become.h"
@@ skipping 21120 matching lines @@
     return false;  // No way they can match.
   }
   intptr_t pos = 0;
   intptr_t str2_pos = 0;
   while (pos < len) {
     int32_t ch = T1::CharAt(str1, pos);
     pos++;
 
     if (ch == Library::kPrivateKeySeparator) {
       // Consume a private key separator.
-      while ((pos < len) && (T1::CharAt(str1, pos) != '.')) {
+      while ((pos < len) && (T1::CharAt(str1, pos) != '.') &&
+             (T1::CharAt(str1, pos) != '&')) {
         pos++;
       }
       // Resume matching characters.
       continue;
     }
     if ((str2_pos == str2_len) || (ch != T2::CharAt(str2, str2_pos))) {
       return false;
     }
     str2_pos++;
   }
@@ skipping 2144 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart