v8: backport pieces from 18a26cfe174 from upstream v8

Backport new virtual methods from 18a26cfe174
("Add memory protection API to ArrayBuffer::Allocator")

PR-URL: #13217
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

deps/v8/include/v8.h

@@ -4008,12 +4008,20 @@ class V8_EXPORT ArrayBuffer : public Object {
      */
     virtual void* AllocateUninitialized(size_t length) = 0;
 
+    virtual void* Reserve(size_t length);
+
     /**
      * Free the memory block of size |length|, pointed to by |data|.
      * That memory is guaranteed to be previously allocated by |Allocate|.
      */
     virtual void Free(void* data, size_t length) = 0;
 
+    enum class AllocationMode { kNormal, kReservation };
+    virtual void Free(void* data, size_t length, AllocationMode mode);
+    enum class Protection { kNoAccess, kReadWrite };
+    virtual void SetProtection(void* data, size_t length,
+                               Protection protection);
+
     /**
      * malloc/free based convenience allocator.
      *

deps/v8/src/api.cc

@@ -437,6 +437,19 @@ void V8::SetSnapshotDataBlob(StartupData* snapshot_blob) {
   i::V8::SetSnapshotBlob(snapshot_blob);
 }
 
+void* v8::ArrayBuffer::Allocator::Reserve(size_t length) { UNIMPLEMENTED(); }
+
+void v8::ArrayBuffer::Allocator::Free(void* data, size_t length,
+                                      AllocationMode mode) {
+  UNIMPLEMENTED();
+}
+
+void v8::ArrayBuffer::Allocator::SetProtection(
+    void* data, size_t length,
+    v8::ArrayBuffer::Allocator::Protection protection) {
+  UNIMPLEMENTED();
+}
+
 namespace {
 
 class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {