Only hightlight the part of suggestion string that has not been typed into input field in

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 583 matching lines @@
   did_set_node_text_ = true;
   node->setEditingValue(value.substr(0, node->maxLength()));
   node->setAutofilled(true);
 }
 
 void AutofillAgent::PreviewFieldWithValue(const base::string16& value,
                                           WebInputElement* node) {
   was_query_node_autofilled_ = element_.isAutofilled();
   node->setSuggestedValue(value.substr(0, node->maxLength()));
   node->setAutofilled(true);
+  node->setSelectionRange(node->value().length(),
+                          node->suggestedValue().length());
 }
 
 void AutofillAgent::HidePopup() {
   if (!is_popup_possibly_visible_)
     return;
 
   if (!element_.isNull())
     OnClearPreviewedForm();
 
   is_popup_possibly_visible_ = false;
   Send(new AutofillHostMsg_HidePopup(routing_id()));
 }
 
 // TODO(isherman): Decide if we want to support non-password autofill with AJAX.
 void AutofillAgent::didAssociateFormControls(const WebVector<WebNode>& nodes) {
   for (size_t i = 0; i < nodes.size(); ++i) {
     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 && !frame->parent()) {
       password_autofill_agent_->OnDynamicFormsSeen(frame);
       return;
     }
   }
 }
 
 }  // namespace autofill