Move NumberToStringStub::GenerateLookupNumberStringCache to the MacroAssembler.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 9f8dafc234718ab73df9f9778bdf2e15163ddc5a..09dae3e09608b248886bd0a7b47a783a9171d25b 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -739,6 +739,17 @@ class MacroAssembler: public Assembler {
   // ---------------------------------------------------------------------------
   // String macros.
 
+  // Generate code to do a lookup in the number string cache. If the number in
+  // the register object is found in the cache the generated code falls through
+  // with the result in the result register. The object and the result register
+  // can be the same. If the number is not found in the cache the code jumps to
+  // the label not_found with only the content of register object unchanged.
+  void LookupNumberStringCache(Register object,
+                               Register result,
+                               Register scratch1,
+                               Register scratch2,
+                               Label* not_found);
+
   // If object is a string, its map is loaded into object_map.
   void JumpIfNotString(Register object,
                        Register object_map,