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

runtime/vm/scavenger.cc

 // 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.
 
 #include "vm/scavenger.h"
 
 #include <algorithm>
 #include <map>
 #include <utility>
 
@@ skipping 653 matching lines @@
 void Scavenger::VisitObjects(ObjectVisitor* visitor) const {
   uword cur = FirstObjectStart();
   while (cur < top_) {
     RawObject* raw_obj = RawObject::FromAddr(cur);
     visitor->VisitObject(raw_obj);
     cur += raw_obj->Size();
   }
 }
 
 
+RawObject* Scavenger::FindObject(FindObjectVisitor* visitor) const {
+  ASSERT(!scavenging_);
+  uword cur = FirstObjectStart();
+  if (visitor->VisitRange(cur, top_)) {
+    while (cur < top_) {
+      RawObject* raw_obj = RawObject::FromAddr(cur);
+      uword next = cur + raw_obj->Size();
+      if (visitor->VisitRange(cur, next) && raw_obj->FindObject(visitor)) {
+        return raw_obj;  // Found object, return it.
+      }
+      cur = next;
+    }
+    ASSERT(cur == top_);
+  }
+  return Object::null();
+}
+
+
 void Scavenger::Scavenge() {
   // TODO(cshapiro): Add a decision procedure for determining when the
   // the API callbacks should be invoked.
   Scavenge(false);
 }
 
 
 void Scavenger::Scavenge(bool invoke_api_callbacks) {
   // Scavenging is not reentrant. Make sure that is the case.
   ASSERT(!scavenging_);
@@ skipping 77 matching lines @@
 
 
 void Scavenger::FreeExternal(intptr_t size) {
   ASSERT(size >= 0);
   external_size_ -= size;
   ASSERT(external_size_ >= 0);
   end_ = Utils::Minimum(to_->end(), end_ + size);
 }
 
 }  // namespace dart