[crankshaft] Remove useless --optimize-for-in flag.

src/crankshaft/hydrogen.cc

 // Copyright 2013 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/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 5272 matching lines @@
                                       break_info.break_block());
   set_current_block(loop_exit);
 }
 
 
 void HOptimizedGraphBuilder::VisitForInStatement(ForInStatement* stmt) {
   DCHECK(!HasStackOverflow());
   DCHECK(current_block() != NULL);
   DCHECK(current_block()->HasPredecessor());
 
-  if (!FLAG_optimize_for_in) {
-    return Bailout(kForInStatementOptimizationIsDisabled);
-  }
-
   if (!stmt->each()->IsVariableProxy() ||
       !stmt->each()->AsVariableProxy()->var()->IsStackLocal()) {
     return Bailout(kForInStatementWithNonLocalEachVariable);
   }
 
   Variable* each_var = stmt->each()->AsVariableProxy()->var();
 
   CHECK_ALIVE(VisitForValue(stmt->enumerable()));
   HValue* enumerable = Top();  // Leave enumerable at the top.
 
@@ skipping 8309 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8