Uses child views in Autofill Popup so we can trigger

chrome/browser/ui/autofill/autofill_popup_controller.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_UI_AUTOFILL_AUTOFILL_POPUP_CONTROLLER_H_
 #define CHROME_BROWSER_UI_AUTOFILL_AUTOFILL_POPUP_CONTROLLER_H_
 
 #include <stddef.h>
 
 #include <vector>
 
 #include "base/compiler_specific.h"
+#include "base/optional.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/autofill/autofill_popup_view_delegate.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/native_theme/native_theme.h"
 
 namespace autofill {
 
 class AutofillPopupLayoutModel;
 struct Suggestion;
 
 // This interface provides data to an AutofillPopupView.
 class AutofillPopupController : public AutofillPopupViewDelegate {
  public:
-  // Recalculates the height and width of the popup and triggers a redraw.
-  virtual void UpdateBoundsAndRedrawPopup() = 0;
+  // Recalculates the height and width of the popup and triggers a redraw when
+  // suggestions change.
+  virtual void OnSuggestionsChanged() = 0;
 
   // Accepts the suggestion at |index|.
   virtual void AcceptSuggestion(size_t index) = 0;
 
   // Returns the number of lines of data that there are.
   virtual size_t GetLineCount() const = 0;
 
   // Returns the suggestion or pre-elided string at the given row index.
   virtual const autofill::Suggestion& GetSuggestionAt(size_t row) const = 0;
   virtual const base::string16& GetElidedValueAt(size_t row) const = 0;
   virtual const base::string16& GetElidedLabelAt(size_t row) const = 0;
 
   // Returns whether the item at |list_index| can be removed. If so, fills
   // out |title| and |body| (when non-null) with relevant user-facing text.
   virtual bool GetRemovalConfirmationText(int index,
                                           base::string16* title,
                                           base::string16* body) = 0;
 
   // Removes the suggestion at the given index.
   virtual bool RemoveSuggestion(int index) = 0;
 
   // Returns the background color ID of the row item according to its |index|,
   // or default popup background otherwise.
   virtual ui::NativeTheme::ColorId GetBackgroundColorIDForRow(
       int index) const = 0;
 
   // Returns the index of the selected line. A line is "selected" when it is
   // hovered or has keyboard focus.
-  virtual int selected_line() const = 0;
+  virtual base::Optional<size_t> selected_line() const = 0;
 
   virtual const AutofillPopupLayoutModel& layout_model() const = 0;
 
  protected:
   ~AutofillPopupController() override {}
 };
 
 }  // namespace autofill
 
 #endif  // CHROME_BROWSER_UI_AUTOFILL_AUTOFILL_POPUP_CONTROLLER_H_