[turbofan] Pull ResizeMergeOrPhi into CommonOperatorBuilder and use in ControlReducer.

src/compiler/common-operator.h

 // Copyright 2013 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_COMMON_OPERATOR_H_
 #define V8_COMPILER_COMMON_OPERATOR_H_
 
 #include "src/compiler/machine-type.h"
 #include "src/unique.h"
 
@@ skipping 183 matching lines @@
   const Operator* ValueEffect(int arguments);
   const Operator* Finish(int arguments);
   const Operator* StateValues(int arguments);
   const Operator* FrameState(
       FrameStateType type, BailoutId bailout_id,
       OutputFrameStateCombine state_combine,
       MaybeHandle<JSFunction> jsfunction = MaybeHandle<JSFunction>());
   const Operator* Call(const CallDescriptor* descriptor);
   const Operator* Projection(size_t index);
 
+  // Constructs a new merge or phi operator with the same opcode as {op}, but
+  // with {size} inputs.
+  const Operator* ResizeMergeOrPhi(const Operator* op, int size);
+
  private:
   Zone* zone() const { return zone_; }
 
   const CommonOperatorGlobalCache& cache_;
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(CommonOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_