Fix for issue 25236

runtime/vm/dart.cc

Index: runtime/vm/dart.cc
diff --git a/runtime/vm/dart.cc b/runtime/vm/dart.cc
index 75689247de36c62c526e186d9aea4ec9f742e5ce..7a17cc32a0199acc00ca2adadfdf387593d194bb 100644
--- a/runtime/vm/dart.cc
+++ b/runtime/vm/dart.cc
@@ -228,7 +228,8 @@ const char* Dart::Cleanup() {
   {
     // Set the VM isolate as current isolate when shutting down
     // Metrics so that we can use a StackZone.
-    Thread::EnterIsolate(vm_isolate_);
+    bool result = Thread::EnterIsolate(vm_isolate_);
+    ASSERT(result);
     Metric::Cleanup();
     Thread::ExitIsolate();
   }
@@ -252,7 +253,8 @@ const char* Dart::Cleanup() {
     thread_pool_ = NULL;
 
     // Set the VM isolate as current isolate.
-    Thread::EnterIsolate(vm_isolate_);
+    bool result = Thread::EnterIsolate(vm_isolate_);
+    ASSERT(result);
 
     ShutdownIsolate();
     vm_isolate_ = NULL;
@@ -407,7 +409,8 @@ void Dart::RunShutdownCallback() {
 void Dart::ShutdownIsolate(Isolate* isolate) {
   ASSERT(Isolate::Current() == NULL);
   // We need to enter the isolate in order to shut it down.
-  Thread::EnterIsolate(isolate);
+  bool result = Thread::EnterIsolate(isolate);
+  ASSERT(result);
   ShutdownIsolate();
   // Since the isolate is shutdown and deleted, there is no need to
   // exit the isolate here.