[Interpreter] Add support for loading globals in the interpreter.

src/interpreter/bytecode-generator.h

Index: src/interpreter/bytecode-generator.h
diff --git a/src/interpreter/bytecode-generator.h b/src/interpreter/bytecode-generator.h
index a192bc66417c04b3274958d17fa449560c1e95bc..99536c33fb52fbf8d092eaff624fdd936ee675e5 100644
--- a/src/interpreter/bytecode-generator.h
+++ b/src/interpreter/bytecode-generator.h
@@ -29,6 +29,7 @@ class BytecodeGenerator : public AstVisitor {
 
   void VisitArithmeticExpression(BinaryOperation* binop);
   void VisitPropertyLoad(Register obj, Property* expr);
+  void VisitVariableLoad(Variable* variable);
 
   inline BytecodeArrayBuilder& builder() { return builder_; }
   inline Scope* scope() const { return scope_; }