Add 'address' vm service message that finds heap objects.

runtime/vm/scavenger.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_SCAVENGER_H_
 #define VM_SCAVENGER_H_
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
@@ skipping 22 matching lines @@
   // During a scavenge this function only returns true for addresses that will
   // be part of the surviving objects.
   bool Contains(uword addr) const {
     // No reasonable algorithm should be checking for objects in from space. At
     // least unless it is debugging code. This might need to be relaxed later,
     // but currently it helps prevent dumb bugs.
     ASSERT(!from_->Contains(addr));
     return to_->Contains(addr);
   }
 
+  RawObject* FindObject(FindObjectVisitor* visitor) const;
+
   uword TryAllocate(intptr_t size) {
     ASSERT(Utils::IsAligned(size, kObjectAlignment));
 #if defined(DEBUG)
     if (FLAG_gc_at_alloc && !scavenging_) {
       Scavenge();
     }
 #endif
     uword result = top_;
     intptr_t remaining = end_ - top_;
     if (remaining < size) {
@@ skipping 161 matching lines @@
 
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // VM_SCAVENGER_H_