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

components/autofill/content/browser/content_autofill_driver.cc

 // Copyright 2014 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/browser/content_autofill_driver.h"
 
 #include "base/command_line.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/autofill/content/common/autofill_messages.h"
 #include "components/autofill/core/browser/autofill_client.h"
@@ skipping 120 matching lines @@
 
 void ContentAutofillDriver::RendererShouldFillFieldWithValue(
     const base::string16& value) {
   if (!RendererIsAvailable())
     return;
   render_frame_host_->Send(new AutofillMsg_FillFieldWithValue(
       render_frame_host_->GetRoutingID(), value));
 }
 
 void ContentAutofillDriver::RendererShouldPreviewFieldWithValue(
-    const base::string16& value) {
+    const base::string16& value,
+    size_t match_start) {
   if (!RendererIsAvailable())
     return;
   render_frame_host_->Send(new AutofillMsg_PreviewFieldWithValue(
-      render_frame_host_->GetRoutingID(), value));
+      render_frame_host_->GetRoutingID(), value, match_start));
 }
 
 void ContentAutofillDriver::PopupHidden() {
   // If the unmask prompt is showing, keep showing the preview. The preview
   // will be cleared when the prompt closes.
   if (!autofill_manager_->IsShowingUnmaskPrompt())
     RendererShouldClearPreviewedForm();
 }
 
 bool ContentAutofillDriver::HandleMessage(const IPC::Message& message) {
@@ skipping 48 matching lines @@
     autofill_manager_->Reset();
 }
 
 void ContentAutofillDriver::SetAutofillManager(
     scoped_ptr<AutofillManager> manager) {
   autofill_manager_ = manager.Pass();
   autofill_manager_->SetExternalDelegate(&autofill_external_delegate_);
 }
 
 }  // namespace autofill