[IndexedDB] Pool and evict leveldb iterators, to save memory

content/browser/indexed_db/leveldb/leveldb_iterator.cc

Index: content/browser/indexed_db/leveldb/leveldb_iterator.cc
diff --git a/content/public/browser/gpu_feature_checker.cc b/content/browser/indexed_db/leveldb/leveldb_iterator.cc
similarity index 62%
copy from content/public/browser/gpu_feature_checker.cc
copy to content/browser/indexed_db/leveldb/leveldb_iterator.cc
index afa1004b76fd5ce4b82f14f896a0f3bf67d70371..106903fe0c175be0655e2414a0259992bbccf4c9 100644
--- a/content/public/browser/gpu_feature_checker.cc
+++ b/content/browser/indexed_db/leveldb/leveldb_iterator.cc
@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/public/browser/gpu_feature_checker.h"
+#include "content/browser/indexed_db/leveldb/leveldb_iterator.h"
 
 namespace content {
 
-GpuFeatureChecker::~GpuFeatureChecker() {}
+bool LevelDBIterator::IsMemoryPurged() const {
+  return false;
+}
 
 }  // namespace content