[wasm] Release compilation time callback earlier

As the {CompilationTimeCallback} does not react to
{kFinishedCompilationChunk}, it does not need to stay alive after a
"final" compilation event.

Drive-by: Make the enum a boolean enum.

R=jkummerow@chromium.org

Bug: v8:12899
Change-Id: Iffacd6e3d9a0f2474a51f07cf01419b2badf98c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3667083
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80940}

src/wasm/compilation-environment.h

@@ -127,14 +127,17 @@ class V8_EXPORT_PRIVATE CompilationEventCallback {
 
   virtual void call(CompilationEvent event) = 0;
 
-  enum class ReleaseAfterFinalEvent { kRelease, kKeep };
+  enum ReleaseAfterFinalEvent : bool {
+    kReleaseAfterFinalEvent = true,
+    kKeepAfterFinalEvent = false
+  };
 
   // Tells the module compiler whether to keep or to release a callback when the
   // compilation state finishes all compilation units. Most callbacks should be
   // released, that's why there is a default implementation, but the callback
   // for code caching with dynamic tiering has to stay alive.
   virtual ReleaseAfterFinalEvent release_after_final_event() {
-    return ReleaseAfterFinalEvent::kRelease;
+    return kReleaseAfterFinalEvent;
   }
 };
 

src/wasm/module-compiler.cc

@@ -1777,11 +1777,6 @@ class CompilationTimeCallback : public CompilationEventCallback {
         native_module_(std::move(native_module)),
         compile_mode_(compile_mode) {}
 
-  // Keep this callback alive to be able to record caching metrics.
-  ReleaseAfterFinalEvent release_after_final_event() override {
-    return CompilationEventCallback::ReleaseAfterFinalEvent::kKeep;
-  }
-
   void call(CompilationEvent compilation_event) override {
     DCHECK(base::TimeTicks::IsHighResolution());
     std::shared_ptr<NativeModule> native_module = native_module_.lock();
@@ -3635,8 +3630,7 @@ void CompilationStateImpl::TriggerCallbacks(
       outstanding_recompilation_functions_ == 0) {
     auto new_end = std::remove_if(
         callbacks_.begin(), callbacks_.end(), [](const auto& callback) {
-          return callback->release_after_final_event() ==
-                 CompilationEventCallback::ReleaseAfterFinalEvent::kRelease;
+          return callback->release_after_final_event();
         });
     callbacks_.erase(new_end, callbacks_.end());
   }

src/wasm/streaming-decoder.cc

@@ -342,7 +342,7 @@ class CompilationChunkFinishedCallback : public CompilationEventCallback {
   }
 
   ReleaseAfterFinalEvent release_after_final_event() override {
-    return CompilationEventCallback::ReleaseAfterFinalEvent::kKeep;
+    return kKeepAfterFinalEvent;
   }
 
  private: