[api] Do not force external GCs when only trying to synchronously process phantom callbacks

src/global-handles.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/global-handles.h"
 
 #include "src/vm-state-inl.h"
@@ skipping 865 matching lines @@
 
 int GlobalHandles::PostGarbageCollectionProcessing(
     GarbageCollector collector, const v8::GCCallbackFlags gc_callback_flags) {
   // Process weak global handle callbacks. This must be done after the
   // GC is completely done, because the callbacks may invoke arbitrary
   // API functions.
   DCHECK(isolate_->heap()->gc_state() == Heap::NOT_IN_GC);
   const int initial_post_gc_processing_count = ++post_gc_processing_count_;
   int freed_nodes = 0;
   bool synchronous_second_pass =
-      (gc_callback_flags & kGCCallbackFlagForced) != 0;
+      (gc_callback_flags &
+       (kGCCallbackFlagForced |
+        kGCCallbackFlagSynchronousPhantomCallbackProcessing)) != 0;
   freed_nodes += DispatchPendingPhantomCallbacks(synchronous_second_pass);
   if (initial_post_gc_processing_count != post_gc_processing_count_) {
     // If the callbacks caused a nested GC, then return.  See comment in
     // PostScavengeProcessing.
     return freed_nodes;
   }
   if (collector == SCAVENGER) {
     freed_nodes += PostScavengeProcessing(initial_post_gc_processing_count);
   } else {
     freed_nodes += PostMarkSweepProcessing(initial_post_gc_processing_count);
@@ skipping 368 matching lines @@
   blocks_[block][offset] = object;
   if (isolate->heap()->InNewSpace(object)) {
     new_space_indices_.Add(size_);
   }
   *index = size_++;
 }
 
 
 }  // namespace internal
 }  // namespace v8