Revert "Background finalization."

runtime/vm/scavenger.cc

Index: runtime/vm/scavenger.cc
diff --git a/runtime/vm/scavenger.cc b/runtime/vm/scavenger.cc
index f68145990d582f609f570401a232c8630bebb2d9..306a78a4978ac104cb62f3d870690a344235ff12 100644
--- a/runtime/vm/scavenger.cc
+++ b/runtime/vm/scavenger.cc
@@ -193,13 +193,10 @@ class ScavengerVisitor : public ObjectPointerVisitor {
 
 class ScavengerWeakVisitor : public HandleVisitor {
  public:
-  ScavengerWeakVisitor(Thread* thread,
-                       Scavenger* scavenger,
-                       FinalizationQueue* finalization_queue) :
-      HandleVisitor(thread),
-      scavenger_(scavenger),
-      queue_(finalization_queue) {
-    ASSERT(scavenger->heap_->isolate() == thread->isolate());
+  explicit ScavengerWeakVisitor(Scavenger* scavenger)
+      :  HandleVisitor(Thread::Current()),
+         scavenger_(scavenger) {
+    ASSERT(scavenger->heap_->isolate() == Thread::Current()->isolate());
   }
 
   void VisitHandle(uword addr) {
@@ -207,7 +204,7 @@ class ScavengerWeakVisitor : public HandleVisitor {
       reinterpret_cast<FinalizablePersistentHandle*>(addr);
     RawObject** p = handle->raw_addr();
     if (scavenger_->IsUnreachable(p)) {
-      handle->UpdateUnreachable(thread()->isolate(), queue_);
+      handle->UpdateUnreachable(thread()->isolate());
     } else {
       handle->UpdateRelocated(thread()->isolate());
     }
@@ -215,7 +212,6 @@ class ScavengerWeakVisitor : public HandleVisitor {
 
  private:
   Scavenger* scavenger_;
-  FinalizationQueue* queue_;
 
   DISALLOW_COPY_AND_ASSIGN(ScavengerWeakVisitor);
 };
@@ -816,14 +812,8 @@ void Scavenger::Scavenge(bool invoke_api_callbacks) {
     int64_t middle = OS::GetCurrentTimeMicros();
     {
       TIMELINE_FUNCTION_GC_DURATION(thread, "WeakHandleProcessing");
-      FinalizationQueue* queue = new FinalizationQueue();
-      ScavengerWeakVisitor weak_visitor(thread, this, queue);
+      ScavengerWeakVisitor weak_visitor(this);
       IterateWeakRoots(isolate, &weak_visitor);
-      if (queue->length() > 0) {
-        Dart::thread_pool()->Run(new BackgroundFinalizer(isolate, queue));
-      } else {
-        delete queue;
-      }
     }
     ProcessWeakReferences();
     page_space->ReleaseDataLock();