Uses child views in Autofill Popup so we can trigger

chrome/browser/ui/autofill/autofill_popup_view_delegate.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_AUTOFILL_AUTOFILL_POPUP_VIEW_DELEGATE_H_
 #define CHROME_BROWSER_UI_AUTOFILL_AUTOFILL_POPUP_VIEW_DELEGATE_H_
 
 #include <stddef.h>
 #include <vector>
 
@@ skipping 42 matching lines @@
   virtual const gfx::RectF& element_bounds() const = 0;
 
   // If the current popup should be displayed in RTL mode.
   virtual bool IsRTL() const = 0;
 
   // Returns the full set of autofill suggestions, if applicable.
   virtual const std::vector<autofill::Suggestion> GetSuggestions() = 0;
 
 #if !defined(OS_ANDROID)
   // Returns elided values and labels for the given |row|.
-  virtual int GetElidedValueWidthForRow(size_t row) = 0;
-  virtual int GetElidedLabelWidthForRow(size_t row) = 0;
+  virtual int GetElidedValueWidthForRow(int row) = 0;
+  virtual int GetElidedLabelWidthForRow(int row) = 0;
 #endif
 
  protected:
   virtual ~AutofillPopupViewDelegate() {}
 };
 
 }  // namespace autofill
 
 #endif  // CHROME_BROWSER_UI_AUTOFILL_AUTOFILL_POPUP_VIEW_DELEGATE_H_