Refactor ChooserDialogView to use borders instead of content margins.

chrome/browser/chooser_controller/chooser_controller.h

 // Copyright 2016 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_CHOOSER_CONTROLLER_CHOOSER_CONTROLLER_H_
 #define CHROME_BROWSER_CHOOSER_CONTROLLER_CHOOSER_CONTROLLER_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 112 matching lines @@
   // Open help center URL.
   virtual void OpenHelpCenterUrl() const = 0;
 
   // Provide help information when the adapter is off.
   virtual void OpenAdapterOffHelpUrl() const;
 
   // Only one view may be registered at a time.
   void set_view(View* view) { view_ = view; }
   View* view() const { return view_; }
 
+ protected:
+  void set_title_for_testing(const base::string16& title) { title_ = title; }
+
  private:
   base::string16 title_;
   View* view_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(ChooserController);
 };
 
 #endif  // CHROME_BROWSER_CHOOSER_CONTROLLER_CHOOSER_CONTROLLER_H_