Remove background finalization.

runtime/vm/gc_marker.cc

Index: runtime/vm/gc_marker.cc
diff --git a/runtime/vm/gc_marker.cc b/runtime/vm/gc_marker.cc
index a6d1548671dd3da103cd25dcc5a4b244041720b7..fd1a1f25b8f5cde5d8e2344770429ba55bac27ac 100644
--- a/runtime/vm/gc_marker.cc
+++ b/runtime/vm/gc_marker.cc
@@ -430,21 +430,18 @@ static bool IsUnreachable(const RawObject* raw_obj) {
 
 class MarkingWeakVisitor : public HandleVisitor {
  public:
-  MarkingWeakVisitor(Thread* thread, FinalizationQueue* queue)
-      : HandleVisitor(thread), queue_(queue) {}
+  explicit MarkingWeakVisitor(Thread* thread) : HandleVisitor(thread) {}
 
   void VisitHandle(uword addr) {
     FinalizablePersistentHandle* handle =
         reinterpret_cast<FinalizablePersistentHandle*>(addr);
     RawObject* raw_obj = handle->raw();
     if (IsUnreachable(raw_obj)) {
-      handle->UpdateUnreachable(thread()->isolate(), queue_);
+      handle->UpdateUnreachable(thread()->isolate());
     }
   }
 
  private:
-  FinalizationQueue* queue_;
-
   DISALLOW_COPY_AND_ASSIGN(MarkingWeakVisitor);
 };
 
@@ -711,19 +708,8 @@ void GCMarker::MarkObjects(Isolate* isolate,
       mark.DrainMarkingStack();
       {
         TIMELINE_FUNCTION_GC_DURATION(thread, "WeakHandleProcessing");
-        if (FLAG_background_finalization) {
-          FinalizationQueue* queue = new FinalizationQueue();
-          MarkingWeakVisitor mark_weak(thread, queue);
-          IterateWeakRoots(isolate, &mark_weak);
-          if (queue->length() > 0) {
-            Dart::thread_pool()->Run(new BackgroundFinalizer(isolate, queue));
-          } else {
-            delete queue;
-          }
-        } else {
-          MarkingWeakVisitor mark_weak(thread, NULL);
-          IterateWeakRoots(isolate, &mark_weak);
-        }
+        MarkingWeakVisitor mark_weak(thread);
+        IterateWeakRoots(isolate, &mark_weak);
       }
       // All marking done; detach code, etc.
       FinalizeResultsFrom(&mark);
@@ -764,19 +750,8 @@ void GCMarker::MarkObjects(Isolate* isolate,
       // Phase 2: Weak processing on main thread.
       {
         TIMELINE_FUNCTION_GC_DURATION(thread, "WeakHandleProcessing");
-        if (FLAG_background_finalization) {
-          FinalizationQueue* queue = new FinalizationQueue();
-          MarkingWeakVisitor mark_weak(thread, queue);
-          IterateWeakRoots(isolate, &mark_weak);
-          if (queue->length() > 0) {
-            Dart::thread_pool()->Run(new BackgroundFinalizer(isolate, queue));
-          } else {
-            delete queue;
-          }
-        } else {
-          MarkingWeakVisitor mark_weak(thread, NULL);
-          IterateWeakRoots(isolate, &mark_weak);
-        }
+        MarkingWeakVisitor mark_weak(thread);
+        IterateWeakRoots(isolate, &mark_weak);
       }
       barrier.Sync();