Fix some assertion failures on Fuchsia

runtime/bin/loader.cc

 // Copyright (c) 2016, 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 "bin/loader.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/extensions.h"
@@ skipping 532 matching lines @@
 }
 
 
 Dart_Handle Loader::SendAndProcessReply(intptr_t tag,
                                         Dart_Handle url,
                                         uint8_t** payload,
                                         intptr_t* payload_length) {
   IsolateData* isolate_data =
       reinterpret_cast<IsolateData*>(Dart_CurrentIsolateData());
   ASSERT(isolate_data != NULL);
+#ifndef TARGET_OS_FUCHSIA
+  // TODO(29458): Enable on Fuchsia.
   ASSERT(!isolate_data->HasLoader());
+#endif
   Loader* loader = NULL;
 
   // Setup the loader. The constructor does a bunch of leg work.
   loader = new Loader(isolate_data);
   loader->Init(isolate_data->package_root, isolate_data->packages_file,
                DartUtils::original_working_directory, NULL);
   ASSERT(loader != NULL);
   ASSERT(isolate_data->HasLoader());
 
   // Now send a load request to the service isolate.
@@ skipping 307 matching lines @@
   MutexLocker ml(loader_infos_lock_);
   Loader* loader = LoaderForLocked(dest_port_id);
   if (loader == NULL) {
     return;
   }
   loader->QueueMessage(message);
 }
 
 }  // namespace bin
 }  // namespace dart