FileSystem: Prevent iterator from being deleted after database.

storage/browser/fileapi/sandbox_origin_database.cc

Index: storage/browser/fileapi/sandbox_origin_database.cc
diff --git a/storage/browser/fileapi/sandbox_origin_database.cc b/storage/browser/fileapi/sandbox_origin_database.cc
index 85424a2351c8b3f08a5db910cc71491bc3f32d43..9bdadc40fb77b546ea566eea0b996a7125e3e5a8 100644
--- a/storage/browser/fileapi/sandbox_origin_database.cc
+++ b/storage/browser/fileapi/sandbox_origin_database.cc
@@ -331,16 +331,19 @@ bool SandboxOriginDatabase::GetLastPathNumber(int* number) {
     return false;
   }
   // Verify that this is a totally new database, and initialize it.
-  scoped_ptr<leveldb::Iterator> iter(db_->NewIterator(leveldb::ReadOptions()));
-  iter->SeekToFirst();
-  if (iter->Valid()) {  // DB was not empty, but had no last path number!
-    LOG(ERROR) << "File system origin database is corrupt!";
-    return false;
+  {
+    // Scope the iterator to ensure it is deleted before database is closed.
+    scoped_ptr<leveldb::Iterator> iter(
+        db_->NewIterator(leveldb::ReadOptions()));
+    iter->SeekToFirst();
+    if (iter->Valid()) {  // DB was not empty, but had no last path number!
+      LOG(ERROR) << "File system origin database is corrupt!";
+      return false;
+    }
   }
   // This is always the first write into the database.  If we ever add a
   // version number, they should go in in a single transaction.
-  status =
-      db_->Put(leveldb::WriteOptions(), LastPathKey(), std::string("-1"));
+  status = db_->Put(leveldb::WriteOptions(), LastPathKey(), std::string("-1"));
   if (!status.ok()) {
     HandleError(FROM_HERE, status);
     return false;