Fixes a problem with the recovery of contexts in the debugger at closure calls.

runtime/vm/object.h

Index: runtime/vm/object.h
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 5ba48aa5d6e4d773bd883723589c4b1295b94ec4..5b919c5959064fe868420e5854f8edcf55811c24 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -3286,6 +3286,9 @@ class Code : public Object {
     StorePointer(&raw_ptr()->exception_handlers_, handlers.raw());
   }
 
+  // TODO(turnidge): Consider dropping this function and making
+  // everybody use owner().  Currently this function is misused - even
+  // while generating the snapshot.
   RawFunction* function() const {
     return reinterpret_cast<RawFunction*>(raw_ptr()->owner_);
   }
@@ -3457,6 +3460,8 @@ class Context : public Object {
   }
   inline void SetAt(intptr_t context_index, const Instance& value) const;
 
+  void Dump(int indent = 0) const;
+
   static const intptr_t kBytesPerElement = kWordSize;
   static const intptr_t kMaxElements = kSmiMax / kBytesPerElement;