Introduce FeedbackNexus for vector-based ics.

src/type-feedback-vector-inl.h

 // 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.
 
 #ifndef V8_TYPE_FEEDBACK_VECTOR_INL_H_
 #define V8_TYPE_FEEDBACK_VECTOR_INL_H_
 
 #include "src/type-feedback-vector.h"
 
 namespace v8 {
 namespace internal {
 
+int TypeFeedbackVector::ic_metadata_length() const {
+  return FLAG_vector_ics ? VectorICComputer::word_count(ICSlots()) : 0;
+}
+
+
 Handle<Object> TypeFeedbackVector::UninitializedSentinel(Isolate* isolate) {
   return isolate->factory()->uninitialized_symbol();
 }
 
 
 Handle<Object> TypeFeedbackVector::MegamorphicSentinel(Isolate* isolate) {
   return isolate->factory()->megamorphic_symbol();
 }
 
 
@@ skipping 13 matching lines @@
 }
 
 
 Object* TypeFeedbackVector::RawUninitializedSentinel(Heap* heap) {
   return heap->uninitialized_symbol();
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_TYPE_FEEDBACK_VECTOR_INL_H_