heap: Introduce Isolate::RequestGarbageCollectionForTesting with stack state

Once CppHeap moves away from EmbedderHeapTracer, it can no longer be
returned by Isolate::GetEmbedderHeapTracer. Blink currently uses
GetEmbedderHeapTracer to trigger GCs. This CL introduces a variant of
Isolate::RequestGarbageCollectionForTesting to replace that.

Bug: v8:12407
Change-Id: I099989f55291a0daab7d2051072dedddef58dd40
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3293413
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78015}

include/v8-isolate.h

@@ -1134,6 +1134,21 @@ class V8_EXPORT Isolate {
    */
   void RequestGarbageCollectionForTesting(GarbageCollectionType type);
 
+  /**
+   * Request garbage collection with a specific embedderstack state in this
+   * Isolate. It is only valid to call this function if --expose_gc was
+   * specified.
+   *
+   * This should only be used for testing purposes and not to enforce a garbage
+   * collection schedule. It has strong negative impact on the garbage
+   * collection performance. Use IdleNotificationDeadline() or
+   * LowMemoryNotification() instead to influence the garbage collection
+   * schedule.
+   */
+  void RequestGarbageCollectionForTesting(
+      GarbageCollectionType type,
+      EmbedderHeapTracer::EmbedderStackState stack_state);
+
   /**
    * Set the callback to invoke for logging event.
    */

src/api/api.cc

@@ -8562,6 +8562,17 @@ void Isolate::RequestGarbageCollectionForTesting(GarbageCollectionType type) {
   }
 }
 
+void Isolate::RequestGarbageCollectionForTesting(
+    GarbageCollectionType type,
+    EmbedderHeapTracer::EmbedderStackState stack_state) {
+  if (type == kFullGarbageCollection) {
+    reinterpret_cast<i::Isolate*>(this)
+        ->heap()
+        ->SetEmbedderStackStateForNextFinalization(stack_state);
+  }
+  RequestGarbageCollectionForTesting(type);
+}
+
 Isolate* Isolate::GetCurrent() {
   i::Isolate* isolate = i::Isolate::Current();
   return reinterpret_cast<Isolate*>(isolate);