Add methods for finding object by its snapshot id and id for an object

src/heap-profiler.cc

Index: src/heap-profiler.cc
diff --git a/src/heap-profiler.cc b/src/heap-profiler.cc
index 1e4095029f1540353fe71f639124cbbacbe950bd..7413b6e6886a18af5dc391ec32a05d686d467d7c 100644
--- a/src/heap-profiler.cc
+++ b/src/heap-profiler.cc
@@ -212,4 +212,10 @@ Handle<HeapObject> HeapProfiler::FindHeapObjectById(SnapshotObjectId id) {
 }
 
 
+void HeapProfiler::ClearHeapObjectMap() {
+  ids_.Reset(new HeapObjectsMap(heap()));
+  if (!is_tracking_allocations()) is_tracking_object_moves_ = false;
+}
+
+
 } }  // namespace v8::internal