[IndexedDB] Fix cursor pooling IsValid().

content/browser/indexed_db/leveldb/leveldb_iterator_impl.cc

Index: content/browser/indexed_db/leveldb/leveldb_iterator_impl.cc
diff --git a/content/browser/indexed_db/leveldb/leveldb_iterator_impl.cc b/content/browser/indexed_db/leveldb/leveldb_iterator_impl.cc
index b94a3d6150bee704eba43cefa3224682b9e08f60..eecc77c6323be06f74c5266e8d813788c4fb8af4 100644
--- a/content/browser/indexed_db/leveldb/leveldb_iterator_impl.cc
+++ b/content/browser/indexed_db/leveldb/leveldb_iterator_impl.cc
@@ -38,8 +38,16 @@ leveldb::Status LevelDBIteratorImpl::CheckStatus() {
 }
 
 bool LevelDBIteratorImpl::IsValid() const {
-  return iterator_state_ == IteratorState::EVICTED_AND_VALID ||
-         iterator_->Valid();
+  switch (iterator_state_) {
+    case IteratorState::EVICTED_AND_VALID:
+      return true;
+    case IteratorState::EVICTED_AND_INVALID:
+      return false;
+    case IteratorState::ACTIVE:
+      return iterator_->Valid();
+  }
+  NOTREACHED();
+  return false;
 }
 
 leveldb::Status LevelDBIteratorImpl::SeekToLast() {