Ensure the url provided to a library has a computed hash code

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 10346 matching lines @@
                                     Heap::kOld);
   return reinterpret_cast<RawLibrary*>(raw);
 }
 
 
 RawLibrary* Library::NewLibraryHelper(const String& url,
                                       bool import_core_lib) {
   Thread* thread = Thread::Current();
   Zone* zone = thread->zone();
   ASSERT(thread->IsMutatorThread());
+  // Force the url to have a hash code.
+  url.Hash();
   const Library& result = Library::Handle(zone, Library::New());
   result.StorePointer(&result.raw_ptr()->name_, Symbols::Empty().raw());
   result.StorePointer(&result.raw_ptr()->url_, url.raw());
   result.StorePointer(&result.raw_ptr()->resolved_names_,
                       Object::empty_array().raw());
   result.StorePointer(&result.raw_ptr()->exported_names_,
                       Array::null());
   result.StorePointer(&result.raw_ptr()->dictionary_,
                       Object::empty_array().raw());
   result.StorePointer(&result.raw_ptr()->metadata_,
@@ skipping 12289 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart