[heap] Integrate embedder heap tracer into incremental marking

src/heap/mark-compact.cc

 // Copyright 2012 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/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 2188 matching lines @@
   top_ = bottom_ = 0xdecbad;
   in_use_ = false;
 }
 
 void MarkCompactCollector::SetEmbedderHeapTracer(EmbedderHeapTracer* tracer) {
   DCHECK_NOT_NULL(tracer);
   CHECK_NULL(embedder_heap_tracer_);
   embedder_heap_tracer_ = tracer;
 }
 
+bool MarkCompactCollector::RequiresImmediateWrapperProcessing() {
+  const size_t kTooManyWrappers = 16000;
+  return wrappers_to_trace_.size() > kTooManyWrappers;
+}
+
 void MarkCompactCollector::RegisterWrappersWithEmbedderHeapTracer() {
   DCHECK(UsingEmbedderHeapTracer());
   if (wrappers_to_trace_.empty()) {
     return;
   }
   embedder_heap_tracer()->RegisterV8References(wrappers_to_trace_);
   wrappers_to_trace_.clear();
 }
 
 void MarkCompactCollector::TracePossibleWrapper(JSObject* js_object) {
@@ skipping 1816 matching lines @@
       // The target is always in old space, we don't have to record the slot in
       // the old-to-new remembered set.
       DCHECK(!heap()->InNewSpace(target));
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8