Enable TabManager on Linux

chrome/browser/browser_process_impl.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.
 
 // When each service is created, we set a flag indicating this. At this point,
 // the service initialization could fail or succeed. This allows us to remember
 // if we tried to create a service, and not try creating it over and over if
 // the creation failed.
 
 #ifndef CHROME_BROWSER_BROWSER_PROCESS_IMPL_H_
@@ skipping 313 matching lines @@
 #endif
 
   std::unique_ptr<network_time::NetworkTimeTracker> network_time_tracker_;
 
   std::unique_ptr<gcm::GCMDriver> gcm_driver_;
 
   std::unique_ptr<ChromeChildProcessWatcher> child_process_watcher_;
 
   std::unique_ptr<ChromeDeviceClient> device_client_;
 
-#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_CHROMEOS)
+#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
   // Any change to this #ifdef must be reflected as well in
   // chrome/browser/memory/tab_manager_browsertest.cc
   std::unique_ptr<memory::TabManager> tab_manager_;
 #endif
 
   shell_integration::DefaultWebClientState cached_default_web_client_state_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserProcessImpl);
 };
 
 #endif  // CHROME_BROWSER_BROWSER_PROCESS_IMPL_H_