heap: Forbid inheriting from more containers

Inheriting from Heap* containers is dangerous because of missing
virtual destructors and trace methods.

This only leaves HeapHashSet as container that can be inherited from,
which has one actual use in production code.

Bug: 1056170
Change-Id: I66a301754adb4d970ccc631f1113edcb915c3abc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2589855Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836765}

third_party/blink/renderer/platform/heap/impl/heap_allocator.h

@@ -183,12 +183,12 @@ template <typename KeyArg,
           typename HashArg = typename DefaultHash<KeyArg>::Hash,
           typename KeyTraitsArg = HashTraits<KeyArg>,
           typename MappedTraitsArg = HashTraits<MappedArg>>
-class HeapHashMap : public HashMap<KeyArg,
-                                   MappedArg,
-                                   HashArg,
-                                   KeyTraitsArg,
-                                   MappedTraitsArg,
-                                   HeapAllocator> {
+class HeapHashMap final : public HashMap<KeyArg,
+                                         MappedArg,
+                                         HashArg,
+                                         KeyTraitsArg,
+                                         MappedTraitsArg,
+                                         HeapAllocator> {
   IS_GARBAGE_COLLECTED_CONTAINER_TYPE();
   DISALLOW_NEW();
 
@@ -262,7 +262,7 @@ struct GCInfoTrait<HeapHashSet<T, U, V>>
 template <typename Value,
           typename HashFunctions = typename DefaultHash<Value>::Hash,
           typename Traits = HashTraits<Value>>
-class HeapHashCountedSet
+class HeapHashCountedSet final
     : public HashCountedSet<Value, HashFunctions, Traits, HeapAllocator> {
   IS_GARBAGE_COLLECTED_CONTAINER_TYPE();
   DISALLOW_NEW();
@@ -292,7 +292,7 @@ struct GCInfoTrait<HeapHashCountedSet<T, U, V>>
     : public GCInfoTrait<HashCountedSet<T, U, V, HeapAllocator>> {};
 
 template <typename T, wtf_size_t inlineCapacity = 0>
-class HeapVector : public Vector<T, inlineCapacity, HeapAllocator> {
+class HeapVector final : public Vector<T, inlineCapacity, HeapAllocator> {
   IS_GARBAGE_COLLECTED_CONTAINER_TYPE();
   DISALLOW_NEW();
 
@@ -369,7 +369,7 @@ struct GCInfoTrait<HeapVector<T, inlineCapacity>>
     : public GCInfoTrait<Vector<T, inlineCapacity, HeapAllocator>> {};
 
 template <typename T>
-class HeapDeque : public Deque<T, 0, HeapAllocator> {
+class HeapDeque final : public Deque<T, 0, HeapAllocator> {
   IS_GARBAGE_COLLECTED_CONTAINER_TYPE();
   DISALLOW_NEW();