Reland https://code.google.com/p/dart/source/detail?r=29315:

runtime/lib/isolate.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 "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
@@ skipping 197 matching lines @@
   MutexLocker ml(state->isolate()->mutex());
   state->isolate()->set_spawn_data(reinterpret_cast<uword>(state));
   if (state->isolate()->is_runnable()) {
     state->isolate()->Run();
   }
 
   return port.raw();
 }
 
 
-DEFINE_NATIVE_ENTRY(isolate_spawnFunction, 1) {
+DEFINE_NATIVE_ENTRY(Isolate_spawnFunction, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, closure, arguments->NativeArgAt(0));
   bool throw_exception = false;
   Function& func = Function::Handle();
   if (closure.IsClosure()) {
     func = Closure::function(closure);
     const Class& cls = Class::Handle(func.Owner());
     if (!func.IsClosureFunction() || !func.is_static() || !cls.IsTopLevel()) {
       throw_exception = true;
     }
   } else {
     throw_exception = true;
   }
   if (throw_exception) {
     const String& msg = String::Handle(String::New(
         "Isolate.spawn expects to be passed a top-level function"));
     Exceptions::ThrowArgumentError(msg);
   }
 
 #if defined(DEBUG)
   Context& ctx = Context::Handle();
   ctx = Closure::context(closure);
   ASSERT(ctx.num_variables() == 0);
 #endif
 
   return Spawn(arguments, new IsolateSpawnState(func));
 }
 
 
-DEFINE_NATIVE_ENTRY(isolate_spawnUri, 1) {
+DEFINE_NATIVE_ENTRY(Isolate_spawnUri, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(String, uri, arguments->NativeArgAt(0));
 
   // Canonicalize the uri with respect to the current isolate.
   char* error = NULL;
   char* canonical_uri = NULL;
   const Library& root_lib =
       Library::Handle(arguments->isolate()->object_store()->root_library());
   if (!CanonicalizeUri(arguments->isolate(), root_lib, uri,
                        &canonical_uri, &error)) {
     const String& msg = String::Handle(String::New(error));
     ThrowIsolateSpawnException(msg);
   }
 
   return Spawn(arguments, new IsolateSpawnState(canonical_uri));
 }
 
 
-DEFINE_NATIVE_ENTRY(isolate_getPortInternal, 0) {
+DEFINE_NATIVE_ENTRY(Isolate_mainPort, 0) {
   const Object& port = Object::Handle(ReceivePortCreate(isolate->main_port()));
   if (port.IsError()) {
     Exceptions::PropagateError(Error::Cast(port));
   }
   return port.raw();
 }
 
 }  // namespace dart