Add a flag that lets the webstore show a different UI on app install.

chrome/browser/ui/views/tabs/abstract_tab_strip_view.h

 // Copyright (c) 2011 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_VIEWS_TABS_ABSTRACT_TAB_STRIP_VIEW_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_ABSTRACT_TAB_STRIP_VIEW_H_
 #pragma once
 
 #include "views/view.h"
 
@@ skipping 14 matching lines @@
   // Updates the loading animations displayed by tabs in the tabstrip to the
   // next frame.
   virtual void UpdateLoadingAnimations() = 0;
 
   // Returns true if the specified point(TabStrip coordinates) is
   // in the window caption area of the browser window.
   virtual bool IsPositionInWindowCaption(const gfx::Point& point) = 0;
 
   // Set the background offset used by inactive tabs to match the frame image.
   virtual void SetBackgroundOffset(const gfx::Point& offset) = 0;
+
+  // Returns the new tab button, or NULL if there isn't one.
+  virtual views::View* GetNewTabButton() = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_ABSTRACT_TAB_STRIP_VIEW_H_
-