[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/message_loop/message_loop.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "components/autofill/content/common/autofill_messages.h"
 #include "components/autofill/content/renderer/form_autofill_util.h"
 #include "components/autofill/content/renderer/page_click_tracker.h"
 #include "components/autofill/content/renderer/password_autofill_agent.h"
 #include "components/autofill/content/renderer/password_generation_agent.h"
 #include "components/autofill/core/common/autofill_constants.h"
 #include "components/autofill/core/common/autofill_data_validation.h"
 #include "components/autofill/core/common/autofill_switches.h"
+#include "components/autofill/core/common/autofill_util.h"
 #include "components/autofill/core/common/form_data.h"
 #include "components/autofill/core/common/form_data_predictions.h"
 #include "components/autofill/core/common/form_field_data.h"
 #include "components/autofill/core/common/password_form.h"
 #include "components/autofill/core/common/web_element_descriptor.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/ssl_status.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_view.h"
@@ skipping 686 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());
+
+  if (IsFeatureSubstringMatchEnabled()) {
+    size_t start = autofill::GetTextSelectionStart(value, node->value());
+    if (start != base::string16::npos)
+      node->setSelectionRange(start, node->suggestedValue().length());
+  } else {
+    node->setSelectionRange(node->value().length(),
+                            node->suggestedValue().length());
+  }
 }
 
 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 49 matching lines @@
 
 void AutofillAgent::LegacyAutofillAgent::OnDestruct() {
   // No-op. Don't delete |this|.
 }
 
 void AutofillAgent::LegacyAutofillAgent::FocusChangeComplete() {
   agent_->FocusChangeComplete();
 }
 
 }  // namespace autofill