Experiment to hide close buttons of inactive tabs when using touch

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 195 matching lines @@
   // Stops any ongoing animations. If |layout| is true and an animation is
   // ongoing this does a layout.
   void StopAnimating(bool layout);
 
   // Called to indicate whether the given URL is a supported file.
   void FileSupported(const GURL& url, bool supported);
 
   // TabController overrides:
   const ui::ListSelectionModel& GetSelectionModel() override;
   bool SupportsMultipleSelection() override;
+  bool TouchWasUsedAsLastInput() override;
   void SelectTab(Tab* tab) override;
   void ExtendSelectionTo(Tab* tab) override;
   void ToggleSelected(Tab* tab) override;
   void AddSelectionFromAnchorTo(Tab* tab) override;
   void CloseTab(Tab* tab, CloseTabSource source) override;
   void ToggleTabAudioMute(Tab* tab) override;
   void ShowContextMenuForTab(Tab* tab,
                              const gfx::Point& p,
                              ui::MenuSourceType source_type) override;
   bool IsActiveTab(const Tab* tab) const override;
@@ skipping 446 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_