[Leveldb] Use std::{string,vector} instead of mojo::{String,Array}.

components/leveldb/public/cpp/remote_iterator.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/leveldb/public/cpp/remote_iterator.h"
 
 #include "components/leveldb/public/cpp/util.h"
 
 namespace leveldb {
 
@@ skipping 16 matching lines @@
   database_->IteratorSeekToFirst(iterator_id_, &valid_, &status_, &key_,
                                  &value_);
 }
 
 void RemoteIterator::SeekToLast() {
   database_->IteratorSeekToLast(iterator_id_, &valid_, &status_, &key_,
                                 &value_);
 }
 
 void RemoteIterator::Seek(const Slice& target) {
-  database_->IteratorSeek(iterator_id_, GetArrayFor(target), &valid_, &status_,
+  database_->IteratorSeek(iterator_id_, GetVectorFor(target), &valid_, &status_,
                           &key_, &value_);
 }
 
 void RemoteIterator::Next() {
   database_->IteratorNext(iterator_id_, &valid_, &status_, &key_, &value_);
 }
 
 void RemoteIterator::Prev() {
   database_->IteratorPrev(iterator_id_, &valid_, &status_, &key_, &value_);
 }
 
 Slice RemoteIterator::key() const {
-  return GetSliceFor(key_);
+  if (!key_)
+    return leveldb::Slice();
+  return GetSliceFor(*key_);
 }
 
 Slice RemoteIterator::value() const {
-  return GetSliceFor(value_);
+  if (!value_)
+    return leveldb::Slice();
+  return GetSliceFor(*value_);
 }
 
 Status RemoteIterator::status() const {
-  return DatabaseErrorToStatus(status_, GetSliceFor(key_), GetSliceFor(value_));
+  return DatabaseErrorToStatus(status_, key(), value());
 }
 
 }  // namespace leveldb