Set the loaded_ flag in RawLibrary when it is completely loaded. This

vm/bootstrap.cc

 // Copyright (c) 2011, 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/bootstrap.h"
 
 #include "include/dart_api.h"
 
 #include "vm/bootstrap_natives.h"
 #include "vm/compiler.h"
@@ skipping 63 matching lines @@
   return result.raw();
 }
 
 
 void Bootstrap::Compile(const Library& library, const Script& script) {
   if (FLAG_print_bootstrap) {
     OS::Print("Bootstrap source '%s':\n%s\n",
         String::Handle(script.url()).ToCString(),
         String::Handle(script.source()).ToCString());
   }
+  library.SetLoadInProgress();
   Compiler::Compile(library, script);
+  library.SetLoaded();
 }
 
 
 void Bootstrap::SetupNativeResolver() {
   Library& library = Library::Handle(Library::CoreLibrary());
   ASSERT(!library.IsNull());
   library.set_native_entry_resolver(
       reinterpret_cast<Dart_NativeEntryResolver>(native_lookup));
   library = Library::CoreImplLibrary();
   ASSERT(!library.IsNull());
   library.set_native_entry_resolver(
       reinterpret_cast<Dart_NativeEntryResolver>(native_lookup));
 }
 
 }  // namespace dart