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

components/autofill/core/browser/autofill_external_delegate.cc

Index: components/autofill/core/browser/autofill_external_delegate.cc
diff --git a/components/autofill/core/browser/autofill_external_delegate.cc b/components/autofill/core/browser/autofill_external_delegate.cc
index eda826ca05cbc9887b2d98fe217e54e71d3752e3..a4830cb3880d573707caba8442bbfa93b8c333b7 100644
--- a/components/autofill/core/browser/autofill_external_delegate.cc
+++ b/components/autofill/core/browser/autofill_external_delegate.cc
@@ -186,16 +186,16 @@ void AutofillExternalDelegate::OnPopupHidden() {
   driver_->PopupHidden();
 }
 
-void AutofillExternalDelegate::DidSelectSuggestion(
-    const base::string16& value,
-    int identifier) {
+void AutofillExternalDelegate::DidSelectSuggestion(const base::string16& value,
+                                                   int identifier,
+                                                   size_t match_start) {
   ClearPreviewedForm();
 
   // Only preview the data if it is a profile.
   if (identifier > 0)
     FillAutofillFormData(identifier, true);
   else if (identifier == POPUP_ITEM_ID_AUTOCOMPLETE_ENTRY)
-    driver_->RendererShouldPreviewFieldWithValue(value);
+    driver_->RendererShouldPreviewFieldWithValue(value, match_start);
 }
 
 void AutofillExternalDelegate::DidAcceptSuggestion(const base::string16& value,