Enable TabManager on Linux

chrome/common/chrome_features.cc

 // Copyright 2016 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/common/chrome_features.h"
 
 namespace features {
 
 // All features in alphabetical order.
 
-#if defined(OS_WIN) || defined(OS_MACOSX)
+#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
 // Enables automatic tab discarding, when the system is in low memory state.
 const base::Feature kAutomaticTabDiscarding{"AutomaticTabDiscarding",
                                             base::FEATURE_DISABLED_BY_DEFAULT};
-#endif  // defined(OS_WIN) || defined(OS_MACOSX)
+#endif  // defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
 
 // Enables Expect CT reporting, which sends reports for opted-in sites
 // that don't serve sufficient Certificate Transparency information.
 const base::Feature kExpectCTReporting{"ExpectCTReporting",
                                        base::FEATURE_DISABLED_BY_DEFAULT};
 
 // An experimental fullscreen prototype that allows pages to map browser and
 // system-reserved keyboard shortcuts.
 const base::Feature kExperimentalKeyboardLockUI{
     "ExperimentalKeyboardLockUI", base::FEATURE_DISABLED_BY_DEFAULT};
@@ skipping 43 matching lines @@
                                           base::FEATURE_DISABLED_BY_DEFAULT};
 #endif
 
 #if defined(OS_CHROMEOS)
 // Enables or disables the opt-in IME menu in the language settings page.
 const base::Feature kOptInImeMenu{"OptInImeMenu",
                                   base::FEATURE_ENABLED_BY_DEFAULT};
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace features