Complete switch to SnapshotObjectId.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 49a026be200981d0e7a734c74079952e130441b5..706cfa0ae239e47479e225c6a88acc53bb2f0e0c 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -6019,7 +6019,7 @@ Handle<String> HeapGraphNode::GetName() const {
 }
 
 
-uint64_t HeapGraphNode::GetId() const {
+SnapshotObjectId HeapGraphNode::GetId() const {
   i::Isolate* isolate = i::Isolate::Current();
   IsDeadCheck(isolate, "v8::HeapGraphNode::GetId");
   return ToInternal(this)->id();
@@ -6134,11 +6134,11 @@ const HeapGraphNode* HeapSnapshot::GetRoot() const {
 }
 
 
-const HeapGraphNode* HeapSnapshot::GetNodeById(uint64_t id) const {
+const HeapGraphNode* HeapSnapshot::GetNodeById(SnapshotObjectId id) const {
   i::Isolate* isolate = i::Isolate::Current();
   IsDeadCheck(isolate, "v8::HeapSnapshot::GetNodeById");
   return reinterpret_cast<const HeapGraphNode*>(
-      ToInternal(this)->GetEntryById(static_cast<i::SnapshotObjectId>(id)));
+      ToInternal(this)->GetEntryById(id));
 }