[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

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/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/i18n/case_conversion.h"
@@ skipping 726 matching lines @@
                                        WebInputElement* node) {
   base::AutoReset<bool> auto_reset(&ignore_text_changes_, true);
   node->setEditingValue(value.substr(0, node->maxLength()));
 }
 
 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());
+  PreviewSuggestion(node->suggestedValue(), node->value(), node);
 }
 
 void AutofillAgent::ProcessForms() {
   // Record timestamp of when the forms are first seen. This is used to
   // measure the overhead of the Autofill feature.
   base::TimeTicks forms_seen_timestamp = base::TimeTicks::Now();
 
   WebLocalFrame* frame = render_frame()->GetWebFrame();
   std::vector<FormData> forms = form_cache_.ExtractNewForms();
 
@@ skipping 50 matching lines @@
 
 void AutofillAgent::LegacyAutofillAgent::OnDestruct() {
   // No-op. Don't delete |this|.
 }
 
 void AutofillAgent::LegacyAutofillAgent::FocusChangeComplete() {
   agent_->FocusChangeComplete();
 }
 
 }  // namespace autofill