Remove --experimental-classes flag and related dead code.

src/scopes.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/scopes.h"
 
 #include "src/accessors.h"
 #include "src/bootstrapper.h"
@@ skipping 291 matching lines @@
   // Declare convenience variables.
   // Declare and allocate receiver (even for the script scope, and even
   // if naccesses_ == 0).
   // NOTE: When loading parameters in the script scope, we must take
   // care not to access them as properties of the global object, but
   // instead load them directly from the stack. Currently, the only
   // such parameter is 'this' which is passed on the stack when
   // invoking scripts
   if (is_declaration_scope()) {
     DCHECK(!subclass_constructor || is_function_scope());
-    DCHECK(FLAG_experimental_classes || !subclass_constructor);
     Variable* var = variables_.Declare(
         this, ast_value_factory_->this_string(),
         subclass_constructor ? CONST : VAR, false, Variable::THIS,
         subclass_constructor ? kNeedsInitialization : kCreatedInitialized);
     var->AllocateTo(Variable::PARAMETER, -1);
     receiver_ = var;
 
     if (subclass_constructor) {
       new_target_ = variables_.Declare(
           this, ast_value_factory_->new_target_string(), CONST, false,
@@ skipping 1116 matching lines @@
 }
 
 
 int Scope::ContextLocalCount() const {
   if (num_heap_slots() == 0) return 0;
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
       (function_ != NULL && function_->proxy()->var()->IsContextSlot() ? 1 : 0);
 }
 
 } }  // namespace v8::internal