Replace instances of LINUX2 with OS_CHROMEOS and linux2 with chromeos.

chrome/browser/gtk/tabs/tab_strip_gtk.h

 // Copyright (c) 2009 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_GTK_TABS_TAB_STRIP_GTK_H_
 #define CHROME_BROWSER_GTK_TABS_TAB_STRIP_GTK_H_
 
 #include <gtk/gtk.h>
 #include <vector>
 
@@ skipping 313 matching lines @@
   // Returns true if detach or select changes in the model should be reflected
   // in the TabStrip. This returns false if we're closing all tabs in the
   // TabStrip and so we should prevent updating. This is not const because we
   // use this as a signal to cancel any active animations.
   bool CanUpdateDisplay();
 
   // Notifies the TabStrip that the specified TabAnimation has completed.
   // Optionally a full Layout will be performed, specified by |layout|.
   void FinishAnimation(TabAnimation* animation, bool layout);
 
-#if defined(LINUX2)
+#if defined(OS_CHROMEOS)
   // Creates and returns the tab overview button.
   CustomDrawButton* MakeTabOverviewButton();
 
   // Invoked when the user clicks the tab overview button.
   static void OnTabOverviewButtonClicked(GtkWidget* widget,
                                          TabStripGtk* tabstrip);
 #endif
 
   // The Tabs we contain, and their last generated "good" bounds.
   std::vector<TabData> tab_data_;
@@ skipping 27 matching lines @@
 
   // Our model.
   TabStripModel* model_;
 
   // The currently running animation.
   scoped_ptr<TabAnimation> active_animation_;
 
   // The New Tab button.
   scoped_ptr<CustomDrawButton> newtab_button_;
 
-#if defined(LINUX2)
+#if defined(OS_CHROMEOS)
   // The tab overview button.
   scoped_ptr<CustomDrawButton> tab_overview_button_;
 #endif
 
   // Valid for the lifetime of a drag over us.
   scoped_ptr<DropInfo> drop_info_;
 
   // The controller for a drag initiated from a Tab. Valid for the lifetime of
   // the drag session.
   scoped_ptr<DraggedTabControllerGtk> drag_controller_;
 
   // A factory that is used to construct a delayed callback to the
   // ResizeLayoutTabsNow method.
   ScopedRunnableMethodFactory<TabStripGtk> resize_layout_factory_;
 
   // True if the tabstrip has already been added as a MessageLoop observer.
   bool added_as_message_loop_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TabStripGtk);
 };
 
 #endif  // CHROME_BROWSER_GTK_TABS_TAB_STRIP_GTK_H_