Add CodeStubAssembler::FlattenString

src/code-stub-assembler.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_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 626 matching lines @@
   // Convert any object to a Number.
   compiler::Node* ToNumber(compiler::Node* context, compiler::Node* input);
 
   // Convert any object to a String.
   compiler::Node* ToString(compiler::Node* context, compiler::Node* input);
 
   // Convert any object to a Primitive.
   compiler::Node* JSReceiverToPrimitive(compiler::Node* context,
                                         compiler::Node* input);
 
+  // Convert a String to a flat String.
+  compiler::Node* FlattenString(compiler::Node* string);
+
   enum ToIntegerTruncationMode {
     kNoTruncation,
     kTruncateMinusZero,
   };
 
   // Convert any object to an Integer.
   compiler::Node* ToInteger(compiler::Node* context, compiler::Node* input,
                             ToIntegerTruncationMode mode = kNoTruncation);
 
   // Returns a node that contains a decoded (unsigned!) value of a bit
@@ skipping 438 matching lines @@
   static const int kElementLoopUnrollThreshold = 8;
 };
 
 #define CSA_ASSERT(x) Assert((x), #x, __FILE__, __LINE__)
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_