Replace instances of LINUX2 with OS_CHROMEOS and linux2 with chromeos.

chrome/browser/tab_contents/tab_contents.cc

 // 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.
 
 #include "chrome/browser/tab_contents/tab_contents.h"
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "base/file_version_info.h"
 #include "base/process_util.h"
@@ skipping 239 matching lines @@
       notify_disconnection_(false),
       history_requests_(),
 #if defined(OS_WIN)
       message_box_active_(CreateEvent(NULL, TRUE, FALSE, NULL)),
 #endif
       last_javascript_message_dismissal_(),
       suppress_javascript_messages_(false) {
   pending_install_.page_id = 0;
   pending_install_.callback_functor = NULL;
 
-#if defined(LINUX2)
+#if defined(OS_CHROMEOS)
   // Make sure the thumbnailer is started before starting the render manager.
   // The thumbnailer will want to listen for RVH creations, one of which will
   // happen in RVHManager::Init.
   ThumbnailGenerator* generator = g_browser_process->GetThumbnailGenerator();
   if (generator)
     generator->StartThumbnailing();
 #endif
 
   render_manager_.Init(profile, site_instance, routing_id, modal_dialog_event);
 
@@ skipping 2079 matching lines @@
       NavigationController::LoadCommittedDetails& committed_details =
           *(Details<NavigationController::LoadCommittedDetails>(details).ptr());
       ExpireInfoBars(committed_details);
       break;
     }
 
     default:
       NOTREACHED();
   }
 }