Count closures using the feedback vector cell map, specialize if count==1.

src/compiler/js-create-lowering.h

 // Copyright 2016 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_COMPILER_JS_CREATE_LOWERING_H_
 #define V8_COMPILER_JS_CREATE_LOWERING_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/compiler/graph-reducer.h"
 #include "src/globals.h"
@@ skipping 32 matching lines @@
         native_context_(native_context),
         zone_(zone) {}
   ~JSCreateLowering() final {}
 
   Reduction Reduce(Node* node) final;
 
  private:
   Reduction ReduceJSCreate(Node* node);
   Reduction ReduceJSCreateArguments(Node* node);
   Reduction ReduceJSCreateArray(Node* node);
-  Reduction ReduceJSCreateClosure(Node* node);
   Reduction ReduceJSCreateIterResultObject(Node* node);
   Reduction ReduceJSCreateKeyValueArray(Node* node);
   Reduction ReduceJSCreateLiteral(Node* node);
   Reduction ReduceJSCreateFunctionContext(Node* node);
   Reduction ReduceJSCreateWithContext(Node* node);
   Reduction ReduceJSCreateCatchContext(Node* node);
   Reduction ReduceJSCreateBlockContext(Node* node);
   Reduction ReduceNewArray(Node* node, Node* length, int capacity,
                            Handle<AllocationSite> site);
 
@@ skipping 36 matching lines @@
   MaybeHandle<FeedbackVector> const feedback_vector_;
   Handle<Context> const native_context_;
   Zone* const zone_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_CREATE_LOWERING_H_