Revert "Background finalization."

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 99cb0361b6b2b3c39fec1c4394d1e4fd609517a6..8ed08737a0cdfbcf2035f1acc675afbb7ab959c8 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -1552,8 +1552,7 @@ class FinalizeWeakPersistentHandlesVisitor : public HandleVisitor {
   void VisitHandle(uword addr) {
     FinalizablePersistentHandle* handle =
         reinterpret_cast<FinalizablePersistentHandle*>(addr);
-    FinalizationQueue* queue = NULL;  // Finalize in the foreground.
-    handle->UpdateUnreachable(thread()->isolate(), queue);
+    handle->UpdateUnreachable(thread()->isolate());
   }
 
  private:
@@ -1676,20 +1675,10 @@ void Isolate::Shutdown() {
   if (heap_ != NULL) {
     // Wait for any concurrent GC tasks to finish before shutting down.
     // TODO(koda): Support faster sweeper shutdown (e.g., after current page).
-    {
-      PageSpace* old_space = heap_->old_space();
-      MonitorLocker ml(old_space->tasks_lock());
-      while (old_space->tasks() > 0) {
-        ml.Wait();
-      }
-    }
-
-    // Wait for background finalization to finish before shutting down.
-    {
-      MonitorLocker ml(heap_->finalization_tasks_lock());
-      while (heap_->finalization_tasks() > 0) {
-        ml.Wait();
-      }
+    PageSpace* old_space = heap_->old_space();
+    MonitorLocker ml(old_space->tasks_lock());
+    while (old_space->tasks() > 0) {
+      ml.Wait();
     }
   }