Attempt to use Abseil in QUICHE.

Currently, I am not replacing it fully in order to make a potential rollback easier.

PiperOrigin-RevId: 328561880
Change-Id: I91ad10114f18cf5ca6d89b164f908408385d1c72

common/platform/api/quiche_unordered_containers.h

diff --git a/common/platform/api/quiche_unordered_containers.h b/common/platform/api/quiche_unordered_containers.h
index a53a206..fd0c391 100644
--- a/common/platform/api/quiche_unordered_containers.h
+++ b/common/platform/api/quiche_unordered_containers.h
@@ -7,6 +7,7 @@
 
 #include <functional>
 
+#include "absl/container/node_hash_map.h"
 #include "net/quiche/common/platform/impl/quiche_unordered_containers_impl.h"
 
 namespace quiche {
@@ -16,11 +17,13 @@
 using QuicheDefaultHasher = QuicheDefaultHasherImpl<Key>;
 
 // A general-purpose unordered map.
+// TODO(b/166325009): replace this in code with flat_hash_map/node_hash_map as
+// appropriate.
 template <typename Key,
           typename Value,
           typename Hash = QuicheDefaultHasher<Key>,
           typename Eq = std::equal_to<Key>>
-using QuicheUnorderedMap = QuicheUnorderedMapImpl<Key, Value, Hash, Eq>;
+using QuicheUnorderedMap = absl::node_hash_map<Key, Value, Hash, Eq>;
 
 }  // namespace quiche