WIP: Implement ES6 Spread-calls

src/full-codegen.h

Index: src/full-codegen.h
diff --git a/src/full-codegen.h b/src/full-codegen.h
index 9a2e7460fc3338ae89087f6e5f0f22bce76c7e4e..8c15406810014b8acd3f4eb24f873f8a37f70865 100644
--- a/src/full-codegen.h
+++ b/src/full-codegen.h
@@ -371,6 +371,12 @@ class FullCodeGenerator: public AstVisitor {
   // need the write barrier if location is CONTEXT.
   MemOperand VarOperand(Variable* var, Register scratch);
 
+  // Special visitor for a spread argument, will update a scratch register with
+  // total parameter count, and push each spread value from left to right onto
+  // the stack.
+  void DoSpreadArgument(SpreadOperation* expr, Register arg_count);
+
+
   void VisitForEffect(Expression* expr) {
     EffectContext context(this);
     Visit(expr);