Cache isolate in the StackTrace object to that we don't call

runtime/vm/allocation.h

 // Copyright (c) 2011, 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_ALLOCATION_H_
 #define VM_ALLOCATION_H_
 
 #include "vm/assert.h"
 
 namespace dart {
 
+// Forward declarations.
+class Isolate;
+
 // Stack allocated objects subclass from this base class. Objects of this type
 // cannot be allocated on either the C or object heaps. Destructors for objects
 // of this type will not be run unless the stack is unwound through normal
 // program control flow.
 class ValueObject {
  public:
   ValueObject() { }
   ~ValueObject() { }
 
  private:
   DISALLOW_ALLOCATION();
   // TODO(5411081): Add DISALLOW_COPY_AND_ASSIGN(ValueObject) once the mac
   // build issue is resolved.
 };
 
 
 // Stack resources subclass from this base class. The VM will ensure that the
 // destructors of these objects are called before the stack is unwound past the
 // objects location on the stack. Use stack resource objects if objects
 // need to be destroyed even in the case of exceptions when a Longjump is done
 // to a stack frame above the frame where these objects were allocated.
 class StackResource {
  public:
   StackResource();
   virtual ~StackResource();
 
+  Isolate* isolate() const { return isolate_; }
+
   // The delete operator should be private instead of public, but unfortunately
   // the compiler complains when compiling the destructors for subclasses.
   void operator delete(void* pointer) { UNREACHABLE(); }
 
  private:
+  Isolate* isolate_;  // Current isolate for this stack resource.
   StackResource* previous_;
 
   void* operator new(uword size);
 
   DISALLOW_COPY_AND_ASSIGN(StackResource);
 };
 
 
 // Static allocated classes only contain static members and can never
 // be instantiated in the heap or on the stack.
@@ skipping 27 matching lines @@
   // deallocated by invoking DeleteAll() on the zone they live in.
   void operator delete(void* pointer) { UNREACHABLE(); }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ZoneAllocated);
 };
 
 }  // namespace dart
 
 #endif  // VM_ALLOCATION_H_