Tab close buttons can only be targeted with touch if the whole button is visible

chrome/browser/ui/views/tabs/tab_strip.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_VIEWS_TABS_TAB_STRIP_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_TAB_STRIP_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
@@ skipping 250 matching lines @@
  private:
   typedef std::map<int, std::vector<Tab*> > TabsClosingMap;
 
   class RemoveTabDelegate;
 
   friend class TabDragController;
   friend class TabDragControllerTest;
   FRIEND_TEST_ALL_PREFIXES(TabDragControllerTest, GestureEndShouldEndDragTest);
   friend class TabStripTest;
   FRIEND_TEST_ALL_PREFIXES(TabStripTest, TabHitTestMaskWhenStacked);
+  FRIEND_TEST_ALL_PREFIXES(TabStripTest, ClippedTabCloseButton);
 
   // Used during a drop session of a url. Tracks the position of the drop as
   // well as a window used to highlight where the drop occurs.
   struct DropInfo {
     DropInfo(int drop_index,
              bool drop_before,
              bool point_down,
              views::Widget* context);
     ~DropInfo();
 
@@ skipping 352 matching lines @@
   bool immersive_style_;
 
   // Our observers.
   typedef ObserverList<TabStripObserver> TabStripObservers;
   TabStripObservers observers_;
 
   DISALLOW_COPY_AND_ASSIGN(TabStrip);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_STRIP_H_