Revert of Internalize strings in-place

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index 0700ec7b926d71ac7246566bdb65028ca444d499..be527fa8d30bee06dd8050de27e78315b28853d9 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -712,6 +712,9 @@
   // Convert any object to a Primitive.
   Node* JSReceiverToPrimitive(Node* context, Node* input);
 
+  // Convert a String to a flat String.
+  Node* FlattenString(Node* string);
+
   enum ToIntegerTruncationMode {
     kNoTruncation,
     kTruncateMinusZero,
@@ -815,8 +818,7 @@
 
   // Various building blocks for stubs doing property lookups.
   void TryToName(Node* key, Label* if_keyisindex, Variable* var_index,
-                 Label* if_keyisunique, Variable* var_unique,
-                 Label* if_bailout);
+                 Label* if_keyisunique, Label* if_bailout);
 
   // Calculates array index for given dictionary entry and entry field.
   // See Dictionary::EntryToIndex().