Migrate stack resource unwinding to Thread.

runtime/vm/allocation.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 "vm/allocation.h"
 
 #include "platform/assert.h"
 #include "vm/isolate.h"
 #include "vm/zone.h"
 
@@ skipping 12 matching lines @@
   return Allocate(size, Thread::Current()->zone());
 }
 
 
 void* ZoneAllocated::operator new(uword size, Zone* zone) {
   ASSERT(zone == Thread::Current()->zone());
   return Allocate(size, zone);
 }
 
 
-void StackResource::UnwindAbove(Isolate* isolate, StackResource* new_top) {
-  StackResource* current_resource = isolate->top_resource();
+void StackResource::UnwindAbove(Thread* thread, StackResource* new_top) {
+  StackResource* current_resource = thread->top_resource();
   while (current_resource != new_top) {
     current_resource->~StackResource();
-    current_resource = isolate->top_resource();
+    current_resource = thread->top_resource();
   }
 }
 
 }  // namespace dart