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

content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc

Index: content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc
diff --git a/content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc b/content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc
index c4084948abb6940da102d48df4b622370e5b7bb6..83af4cb9f2ca7e17eaed1a481fe518d4e4c9c25b 100644
--- a/content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc
+++ b/content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc
@@ -167,8 +167,10 @@ const std::string LevelDBTraceTransaction::s_class_name = "LevelDBTransaction";
 class LevelDBTraceIteratorImpl : public LevelDBIteratorImpl {
  public:
   LevelDBTraceIteratorImpl(std::unique_ptr<leveldb::Iterator> iterator,
+                           LevelDBDatabase* db,
+                           const leveldb::Snapshot* snapshot,
                            int inst_num)
-      : LevelDBIteratorImpl(std::move(iterator)),
+      : LevelDBIteratorImpl(std::move(iterator), db, snapshot),
         is_valid_tracer_(s_class_name, "IsValid", inst_num),
         seek_to_last_tracer_(s_class_name, "SeekToLast", inst_num),
         seek_tracer_(s_class_name, "Seek", inst_num),
@@ -224,9 +226,11 @@ const std::string LevelDBTraceIteratorImpl::s_class_name = "LevelDBIterator";
 class LevelDBTestIteratorImpl : public content::LevelDBIteratorImpl {
  public:
   LevelDBTestIteratorImpl(std::unique_ptr<leveldb::Iterator> iterator,
+                          LevelDBDatabase* db,
+                          const leveldb::Snapshot* snapshot,
                           FailMethod fail_method,
                           int fail_on_call_num)
-      : LevelDBIteratorImpl(std::move(iterator)),
+      : LevelDBIteratorImpl(std::move(iterator), db, snapshot),
         fail_method_(fail_method),
         fail_on_call_num_(fail_on_call_num),
         current_call_num_(0) {}
@@ -299,21 +303,25 @@ MockBrowserTestIndexedDBClassFactory::CreateLevelDBTransaction(
 
 std::unique_ptr<LevelDBIteratorImpl>
 MockBrowserTestIndexedDBClassFactory::CreateIteratorImpl(
-    std::unique_ptr<leveldb::Iterator> iterator) {
+    std::unique_ptr<leveldb::Iterator> iterator,
+    LevelDBDatabase* db,
+    const leveldb::Snapshot* snapshot) {
   instance_count_[FAIL_CLASS_LEVELDB_ITERATOR] =
       instance_count_[FAIL_CLASS_LEVELDB_ITERATOR] + 1;
   if (only_trace_calls_) {
     return base::MakeUnique<LevelDBTraceIteratorImpl>(
-        std::move(iterator), instance_count_[FAIL_CLASS_LEVELDB_ITERATOR]);
+        std::move(iterator), db, snapshot,
+        instance_count_[FAIL_CLASS_LEVELDB_ITERATOR]);
   } else {
     if (failure_class_ == FAIL_CLASS_LEVELDB_ITERATOR &&
         instance_count_[FAIL_CLASS_LEVELDB_ITERATOR] ==
             fail_on_instance_num_[FAIL_CLASS_LEVELDB_ITERATOR]) {
       return base::MakeUnique<LevelDBTestIteratorImpl>(
-          std::move(iterator), failure_method_,
+          std::move(iterator), db, snapshot, failure_method_,
           fail_on_call_num_[FAIL_CLASS_LEVELDB_ITERATOR]);
     } else {
-      return base::WrapUnique(new LevelDBIteratorImpl(std::move(iterator)));
+      return base::WrapUnique(
+          new LevelDBIteratorImpl(std::move(iterator), db, snapshot));
     }
   }
 }