[Interpreter] Add support for Load / Store to Lookup slots.

src/interpreter/interpreter.h

Index: src/interpreter/interpreter.h
diff --git a/src/interpreter/interpreter.h b/src/interpreter/interpreter.h
index e993f2b44656cd93bbcf87393d48d737d6ba2d8a..ef9b5d1fe3e7326c8ca711be667dc12863dc38f4 100644
--- a/src/interpreter/interpreter.h
+++ b/src/interpreter/interpreter.h
@@ -95,6 +95,14 @@ class Interpreter {
   void DoDelete(Runtime::FunctionId function_id,
                 compiler::InterpreterAssembler* assembler);
 
+  // Generates code to perform a lookup slot load via |function_id|.
+  void DoLoadLookupSlot(Runtime::FunctionId function_id,
+                        compiler::InterpreterAssembler* assembler);
+
+  // Generates code to perform a lookup slot store depending on |language_mode|.
+  void DoStoreLookupSlot(LanguageMode language_mode,
+                         compiler::InterpreterAssembler* assembler);
+
   bool IsInterpreterTableInitialized(Handle<FixedArray> handler_table);
 
   Isolate* isolate_;