Changed StackZone and ApiZone to be containers for Zone.

runtime/vm/zone.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/zone.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
 #include "vm/isolate.h"
@@ skipping 61 matching lines @@
   return result;
 }
 
 
 Zone::Zone()
     : initial_buffer_(buffer_, kInitialChunkSize),
       position_(initial_buffer_.start()),
       limit_(initial_buffer_.end()),
       head_(NULL),
       large_segments_(NULL),
-      handles_() {
+      handles_(),
+      previous_(NULL) {
 #ifdef DEBUG
     // Zap the entire initial buffer.
   memset(initial_buffer_.pointer(), kZapUninitializedByte,
          initial_buffer_.size());
 #endif
 }
 
 
 Zone::~Zone() {
   DeleteAll();
@@ skipping 106 matching lines @@
     size += s->size();
   }
   OS::Print("Size in bytes allocated, Total = %"Pd" Large Segments = %"Pd"\n",
             SizeInBytes(), size);
 }
 #endif
 
 
 StackZone::StackZone(BaseIsolate* isolate)
     : StackResource(isolate),
-      zone_(),
-      previous_(NULL) {
-  // Assert that there is no current zone as we only want to scope
-  // zones when transitioning from generated dart code to dart VM
-  // runtime code.
-  previous_ = isolate->current_zone();
-  isolate->set_current_zone(this);
+      zone_() {
+  zone_.Link(isolate->current_zone());
+  isolate->set_current_zone(&zone_);
 }
 
 
 StackZone::~StackZone() {
-  ASSERT(isolate()->current_zone() == this);
-  isolate()->set_current_zone(previous_);
+  ASSERT(isolate()->current_zone() == &zone_);
+  isolate()->set_current_zone(zone_.previous_);
 }
 
 
-void StackZone::VisitObjectPointers(ObjectPointerVisitor* visitor) {
-  StackZone* zone = this;
+void Zone::VisitObjectPointers(ObjectPointerVisitor* visitor) {
+  Zone* zone = this;
   while (zone != NULL) {
     zone->handles()->VisitObjectPointers(visitor);
     zone = zone->previous_;
   }
 }
 
 
-char* StackZone::PrintToString(const char* format, ...) {
+char* Zone::PrintToString(const char* format, ...) {
   va_list args;
   va_start(args, format);
   intptr_t len = OS::VSNPrint(NULL, 0, format, args);
   va_end(args);
 
   char* buffer = Alloc<char>(len + 1);
   va_list args2;
   va_start(args2, format);
   OS::VSNPrint(buffer, (len + 1), format, args2);
   va_end(args2);
 
   return buffer;
 }
 
 
 }  // namespace dart