api: Mark explicit write barrier methods as soon deprecated

Explicit write barriers for internal fields are deprecated as they are
automatically emitted by V8.

Depends on:
  https://crrev.com/c/3263924

Bug: v8:12356
Change-Id: I171ba5b42a6570ce52e2e2ea1b7c1029d5a8a3a7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3263888Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77772}

include/v8-cppgc.h

@@ -235,9 +235,13 @@ class V8_EXPORT JSHeapConsistency final {
    * \returns whether a write barrier is needed and which barrier to invoke.
    */
   template <typename HeapHandleCallback>
-  static V8_INLINE WriteBarrierType GetWriteBarrierType(
-      v8::Local<v8::Object>& wrapper, int wrapper_index, const void* wrappable,
-      WriteBarrierParams& params, HeapHandleCallback callback) {
+  V8_DEPRECATE_SOON(
+      "Write barriers automatically emitted when using "
+      "`SetAlignedPointerInInternalFields()`.")
+  static V8_INLINE WriteBarrierType
+      GetWriteBarrierType(v8::Local<v8::Object>& wrapper, int wrapper_index,
+                          const void* wrappable, WriteBarrierParams& params,
+                          HeapHandleCallback callback) {
 #if V8_ENABLE_CHECKS
     CheckWrapper(wrapper, wrapper_index, wrappable);
 #endif  // V8_ENABLE_CHECKS
@@ -270,6 +274,9 @@ class V8_EXPORT JSHeapConsistency final {
    * \param object The pointer to the object. May be an interior pointer to a
    *   an interface of the actual object.
    */
+  V8_DEPRECATE_SOON(
+      "Write barriers automatically emitted when using "
+      "`SetAlignedPointerInInternalFields()`.")
   static V8_INLINE void DijkstraMarkingBarrier(const WriteBarrierParams& params,
                                                cppgc::HeapHandle& heap_handle,
                                                const void* object) {

test/unittests/heap/cppgc-js/unified-heap-unittest.cc

@@ -93,7 +93,12 @@ TEST_F(UnifiedHeapTest, WriteBarrierV8ToCppReference) {
   EXPECT_EQ(0u, Wrappable::destructor_callcount);
 }
 
+#if !defined(_MSC_VER) || defined(__clang__)
+
 TEST_F(UnifiedHeapTest, WriteBarrierV8ToCppReferenceWithExplicitAPI) {
+// TODO(v8:12356): Remove test when fully removing the deprecated API.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
   if (!FLAG_incremental_marking) return;
   v8::HandleScope scope(v8_isolate());
   v8::Local<v8::Context> context = v8::Context::New(v8_isolate());
@@ -118,10 +123,9 @@ TEST_F(UnifiedHeapTest, WriteBarrierV8ToCppReferenceWithExplicitAPI) {
   }
   CollectGarbageWithoutEmbedderStack(cppgc::Heap::SweepingType::kAtomic);
   EXPECT_EQ(0u, Wrappable::destructor_callcount);
+#pragma GCC diagnostic pop
 }
 
-#if !defined(_MSC_VER) || defined(__clang__)
-
 TEST_F(UnifiedHeapTest, WriteBarrierCppToV8Reference) {
 // TODO(v8:12165): Remove test when fully removing the deprecated API.
 #pragma GCC diagnostic push