[Autofill] A bit of cleanup in autofill_agent.cc

components/autofill/content/renderer/autofill_agent.cc

 // Copyright 2013 The Chromium 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 "components/autofill/content/renderer/autofill_agent.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_split.h"
@@ skipping 591 matching lines @@
   }
 
   autofill_action_ = action;
   Send(new AutofillHostMsg_FillAutofillFormData(
       routing_id(), autofill_query_id_, form, field, unique_id));
 }
 
 void AutofillAgent::SetNodeText(const base::string16& value,
                                 blink::WebInputElement* node) {
   did_set_node_text_ = true;
-  base::string16 substring = value;
-  substring = substring.substr(0, node->maxLength());
-
-  node->setEditingValue(substring);
+  node->setEditingValue(value.substr(0, node->maxLength()));
 }
 
 void AutofillAgent::HideAutofillUI() {
   if (!element_.isNull())
     OnClearPreviewedForm();
 
   Send(new AutofillHostMsg_HideAutofillUI(routing_id()));
 }
 
 // TODO(isherman): Decide if we want to support non-password autofill with AJAX.
 void AutofillAgent::didAssociateFormControls(
     const blink::WebVector<blink::WebNode>& nodes) {
   for (size_t i = 0; i < nodes.size(); ++i) {
     blink::WebFrame* frame = nodes[i].document().frame();
     // Only monitors dynamic forms created in the top frame. Dynamic forms
     // inserted in iframes are not captured yet.
     if (!frame->parent()) {
       password_autofill_agent_->OnDynamicFormsSeen(frame);
       return;
     }
   }
 }
 
 }  // namespace autofill