Initial isolate reload support

runtime/vm/heap.h

 // 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.
 
 #ifndef VM_HEAP_H_
 #define VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 348 matching lines @@
   // This heap is in read-only mode: No allocation is allowed.
   bool read_only_;
 
   // GC on the heap is in progress.
   Monitor gc_in_progress_monitor_;
   bool gc_new_space_in_progress_;
   bool gc_old_space_in_progress_;
 
   int pretenure_policy_;
 
+  friend class Become;  // VisitObjectPointers
   friend class ServiceEvent;
   friend class PageSpace;  // VerifyGC
+  friend class IsolateReloadContext;  // VisitObjects
+
   DISALLOW_COPY_AND_ASSIGN(Heap);
 };
 
 
 class HeapIterationScope : public StackResource {
  public:
   HeapIterationScope();
   ~HeapIterationScope();
  private:
   NoSafepointScope no_safepoint_scope_;
@@ skipping 16 matching lines @@
 // Note: During this scope, the code pages are non-executable.
 class WritableVMIsolateScope : StackResource {
  public:
   explicit WritableVMIsolateScope(Thread* thread);
   ~WritableVMIsolateScope();
 };
 
 }  // namespace dart
 
 #endif  // VM_HEAP_H_