Remove the compact nav flag and ensure it is always disabled. Note that the rest of the cnav code...

chrome/browser/about_flags.cc

 // Copyright (c) 2011 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/about_flags.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <set>
@@ skipping 233 matching lines @@
     SINGLE_VALUE_TYPE(switches::kDisableInteractiveFormValidation)
   },
   {
     "focus-existing-tab-on-open",  // FLAGS:RECORD_UMA
     IDS_FLAGS_FOCUS_EXISTING_TAB_ON_OPEN_NAME,
     IDS_FLAGS_FOCUS_EXISTING_TAB_ON_OPEN_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kFocusExistingTabOnOpen)
   },
   {
-    "compact-navigation",
-    IDS_FLAGS_ENABLE_COMPACT_NAVIGATION,
-    IDS_FLAGS_ENABLE_COMPACT_NAVIGATION_DESCRIPTION,
-    kOsWin,  // TODO(stevet): Add other platforms when ready.
-    SINGLE_VALUE_TYPE(switches::kEnableCompactNavigation)
-  },
-  {
     "new-tab-page-4",
     IDS_FLAGS_NEW_TAB_PAGE_4_NAME,
     IDS_FLAGS_NEW_TAB_PAGE_4_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kNewTabPage4)
   },
   {
     "tab-groups-context-menu",
     IDS_FLAGS_TAB_GROUPS_CONTEXT_MENU_NAME,
     IDS_FLAGS_TAB_GROUPS_CONTEXT_MENU_DESCRIPTION,
@@ skipping 527 matching lines @@
 }
 
 const Experiment* GetExperiments(size_t* count) {
   *count = num_experiments;
   return experiments;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags