Fix shutdown crash in Sky

sky/engine/tonic/dart_state.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sky/engine/config.h"
 #include "sky/engine/tonic/dart_state.h"
 
 #include "sky/engine/tonic/dart_class_library.h"
 #include "sky/engine/tonic/dart_converter.h"
 #include "sky/engine/tonic/dart_exception_factory.h"
@@ skipping 14 matching lines @@
       class_library_(adoptPtr(new DartClassLibrary)),
       string_cache_(adoptPtr(new DartStringCache)),
       exception_factory_(adoptPtr(new DartExceptionFactory(this))),
       timer_heap_(adoptPtr(new DartTimerHeap())),
       weak_factory_(this) {
 }
 
 DartState::~DartState() {
 }
 
-void DartState::DidSetIsolateInternal() {
-  {
-    Scope dart_scope(this);
-    index_handle_.Set(this, ToDart("index"));
+void DartState::SetIsolate(Dart_Isolate isolate) {
+  CHECK(!isolate_);
+  isolate_ = isolate;
+  if (isolate_) {

[eseidel, 2015/06/10 19:56:41]

I might have early returned instead.  but ok.

+    {
+      Scope dart_scope(this);
+      index_handle_.Set(this, ToDart("index"));
+    }
+    DidSetIsolate();
   }
-  DidSetIsolate();
 }
 
 DartState* DartState::From(Dart_Isolate isolate) {
   return static_cast<DartState*>(Dart_IsolateData(isolate));
 }
 
 DartState* DartState::Current() {
   return static_cast<DartState*>(Dart_CurrentIsolateData());
 }
 
 base::WeakPtr<DartState> DartState::GetWeakPtr() {
   return weak_factory_.GetWeakPtr();
 }
 
 }  // namespace blink