Remove unnecessary MemberHash<> templates.

third_party/WebKit/Source/platform/heap/Persistent.h

 // Copyright 2016 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 Persistent_h
 #define Persistent_h
 
 #include "platform/heap/Member.h"
 #include "platform/heap/PersistentNode.h"
 #include "wtf/Allocator.h"
@@ skipping 675 matching lines @@
 template<typename T, typename U> inline bool operator==(const Member<T>& a, const Persistent<U>& b) { return a.get() == b.get(); }
 template<typename T, typename U> inline bool operator!=(const Member<T>& a, const Persistent<U>& b) { return a.get() != b.get(); }
 template<typename T, typename U> inline bool operator==(const Persistent<T>& a, const Member<U>& b) { return a.get() == b.get(); }
 template<typename T, typename U> inline bool operator!=(const Persistent<T>& a, const Member<U>& b) { return a.get() != b.get(); }
 
 } // namespace blink
 
 namespace WTF {
 
 template <typename T>
-struct PersistentHash : MemberHash<T> {
-    STATIC_ONLY(PersistentHash);
-};
-
-template <typename T>
-struct CrossThreadPersistentHash : MemberHash<T> {
-    STATIC_ONLY(CrossThreadPersistentHash);
-};
-
-template <typename T>
 struct DefaultHash<blink::Persistent<T>> {
     STATIC_ONLY(DefaultHash);
-    using Hash = PersistentHash<T>;
+    using Hash = MemberHash<T>;
+};
+
+template <typename T>
+struct DefaultHash<blink::WeakPersistent<T>> {
+    STATIC_ONLY(DefaultHash);
+    using Hash = MemberHash<T>;
 };
 
 template <typename T>
 struct DefaultHash<blink::CrossThreadPersistent<T>> {
     STATIC_ONLY(DefaultHash);
-    using Hash = CrossThreadPersistentHash<T>;
+    using Hash = MemberHash<T>;
+};
+
+template <typename T>
+struct DefaultHash<blink::CrossThreadWeakPersistent<T>> {
+    STATIC_ONLY(DefaultHash);
+    using Hash = MemberHash<T>;
 };
 
 template<typename T>
 struct ParamStorageTraits<blink::WeakPersistentThisPointer<T>> {
     STATIC_ONLY(ParamStorageTraits);
     static_assert(sizeof(T), "T must be fully defined");
     using StorageType = blink::WeakPersistent<T>;
 
     static StorageType wrap(const blink::WeakPersistentThisPointer<T>& value) { return value.value(); }
 
@@ skipping 17 matching lines @@
     // into it.
     //
     // TODO(sof): remove this hack once wtf/Functional.h can also work with a type like
     // CrossThreadWeakPersistent<>.
     static WeakPtr<T> unwrap(const StorageType& value) { return WeakPtr<T>(WeakReference<T>::create(value.get())); }
 };
 
 } // namespace WTF
 
 #endif // Persistent_h