Obligatory fix for Win64.

src/profile-generator-inl.h

Index: src/profile-generator-inl.h
diff --git a/src/profile-generator-inl.h b/src/profile-generator-inl.h
index acaf2f1b0e9f7fb2ab2db67c7c0834ca9d16d135..7a70b013bb2b861c2529563e782ace4f95eb3fbd 100644
--- a/src/profile-generator-inl.h
+++ b/src/profile-generator-inl.h
@@ -108,9 +108,10 @@ HeapObject* V8HeapExplorer::GetNthGcSubrootObject(int delta) {
 
 
 int V8HeapExplorer::GetGcSubrootOrder(HeapObject* subroot) {
-  return (reinterpret_cast<char*>(subroot) -
-          reinterpret_cast<char*>(kFirstGcSubrootObject)) /
-      HeapObjectsMap::kObjectIdStep;
+  return static_cast<int>(
+      (reinterpret_cast<char*>(subroot) -
+       reinterpret_cast<char*>(kFirstGcSubrootObject)) /
+      HeapObjectsMap::kObjectIdStep);
 }