Remove SpdyHash, SpdyHashSet, SpdyHashMap, QuicheHashStringPair.

absl::flat_hash_set, absl::flat_hash_map, and absl::Hash are already used
elsewhere is QUICHE.

SpdyHash is not used.

SpdyHashSetImpl and SpdyHashMapImpl are already absl::flat_hash_set and
absl::flat_hash_map in internal code.  They were std::unordered_set and
std::unordered_map in Chromium, but absl hash containers are better according
to https://abseil.io/tips/136.

QuicheHashStringPair is already absl::Hash in Chromium.  Internal code uses a
custom implementation that is officially deprecated in favor of absl::Hash.

PiperOrigin-RevId: 363562364
Change-Id: I3367a242ac376df7cec4662b3d7967d323048806

common/platform/api/quiche_string_piece.h

diff --git a/common/platform/api/quiche_string_piece.h b/common/platform/api/quiche_string_piece.h
deleted file mode 100644
index ca58aae..0000000
--- a/common/platform/api/quiche_string_piece.h
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright (c) 2017 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.
-
-#ifndef QUICHE_COMMON_PLATFORM_API_QUICHE_STRING_PIECE_H_
-#define QUICHE_COMMON_PLATFORM_API_QUICHE_STRING_PIECE_H_
-
-#include "absl/strings/string_view.h"
-#include "net/quiche/common/platform/impl/quiche_string_piece_impl.h"
-
-namespace quiche {
-
-inline size_t QuicheHashStringPair(absl::string_view a, absl::string_view b) {
-  return QuicheHashStringPairImpl(a, b);
-}
-
-}  // namespace quiche
-
-#endif  // QUICHE_COMMON_PLATFORM_API_QUICHE_STRING_PIECE_H_

spdy/core/hpack/hpack_header_table.cc

diff --git a/spdy/core/hpack/hpack_header_table.cc b/spdy/core/hpack/hpack_header_table.cc
index 9e36e2f..006618d 100644
--- a/spdy/core/hpack/hpack_header_table.cc
+++ b/spdy/core/hpack/hpack_header_table.cc
@@ -6,7 +6,6 @@
 
 #include <algorithm>
 
-#include "common/platform/api/quiche_string_piece.h"
 #include "spdy/core/hpack/hpack_constants.h"
 #include "spdy/core/hpack/hpack_static_table.h"
 #include "spdy/platform/api/spdy_containers.h"
@@ -17,7 +16,8 @@
 
 size_t HpackHeaderTable::EntryHasher::operator()(
     const HpackEntry* entry) const {
-  return quiche::QuicheHashStringPair(entry->name(), entry->value());
+  return absl::Hash<std::pair<absl::string_view, absl::string_view>>()(
+      std::make_pair(entry->name(), entry->value()));
 }
 
 bool HpackHeaderTable::EntriesEq::operator()(const HpackEntry* lhs,

spdy/core/hpack/hpack_header_table.h

diff --git a/spdy/core/hpack/hpack_header_table.h b/spdy/core/hpack/hpack_header_table.h
index 88a656f..d6ea206 100644
--- a/spdy/core/hpack/hpack_header_table.h
+++ b/spdy/core/hpack/hpack_header_table.h
@@ -11,6 +11,8 @@
 #include <memory>
 
 #include "absl/base/attributes.h"
+#include "absl/container/flat_hash_map.h"
+#include "absl/container/flat_hash_set.h"
 #include "absl/hash/hash.h"
 #include "absl/strings/string_view.h"
 #include "common/platform/api/quiche_export.h"
@@ -50,10 +52,10 @@
   struct QUICHE_EXPORT_PRIVATE EntriesEq {
     bool operator()(const HpackEntry* lhs, const HpackEntry* rhs) const;
   };
-  using UnorderedEntrySet = SpdyHashSet<HpackEntry*, EntryHasher, EntriesEq>;
-  using NameToEntryMap = SpdyHashMap<absl::string_view,
-                                     const HpackEntry*,
-                                     absl::Hash<absl::string_view>>;
+  using UnorderedEntrySet =
+      absl::flat_hash_set<HpackEntry*, EntryHasher, EntriesEq>;
+  using NameToEntryMap =
+      absl::flat_hash_map<absl::string_view, const HpackEntry*>;
 
   HpackHeaderTable();
   HpackHeaderTable(const HpackHeaderTable&) = delete;

spdy/platform/api/spdy_containers.h

diff --git a/spdy/platform/api/spdy_containers.h b/spdy/platform/api/spdy_containers.h
index a1a00e6..33da399 100644
--- a/spdy/platform/api/spdy_containers.h
+++ b/spdy/platform/api/spdy_containers.h
@@ -9,19 +9,6 @@
 
 namespace spdy {
 
-template <typename KeyType>
-using SpdyHash = SpdyHashImpl<KeyType>;
-
-// SpdyHashMap does not guarantee pointer stability.
-template <typename KeyType,
-          typename ValueType,
-          typename Hash = SpdyHash<KeyType>>
-using SpdyHashMap = SpdyHashMapImpl<KeyType, ValueType, Hash>;
-
-// SpdyHashSet does not guarantee pointer stability.
-template <typename ElementType, typename Hasher, typename Eq>
-using SpdyHashSet = SpdyHashSetImpl<ElementType, Hasher, Eq>;
-
 // A map which offers insertion-ordered iteration.
 template <typename Key, typename Value, typename Hash, typename Eq>
 using SpdyLinkedHashMap = SpdyLinkedHashMapImpl<Key, Value, Hash, Eq>;